Hello,
during AIO install with
ovirt-engine-setup-3.2.0-1.20121217.git1e01c00.fc18.noarch

I specified ISO domain not accepting default but setting /ISO

Host correctly activated but no ISO domain found.

I can see:
[g.cecchi@f18aio ~]$ cat /etc/exports
/ISO 0.0.0.0/0.0.0.0(rw) #rhev installer

[g.cecchi@f18aio ~]$ sudo exportfs -v
/ISO           0.0.0.0/0.0.0.0(rw,wdelay,root_squash,no_subtree_check)

I cannot add the domain because I get:

Error while executing action New Local Storage Domain: Error in creating a Storage Domain. The selected storage path is not empty (probably contains another Storage Domain). Either remove the existing Storage Domain from this path, or change the Storage path).

I cannot import that domain because if I specify:
Domain Function / Storage Type : ISO/NFS
Use Host : local_host
Export Path : f18aio:/ISO

I get
There is no storage domain under the specified path. Check event log for more details.

In messages:
Dec 20 12:33:03 f18aio rpc.mountd[1576]: authenticated mount request from 192.168.122.160:871 for /ISO (/ISO)
Dec 20 12:33:05 f18aio kernel: [ 4748.963964] ata1: soft resetting link
Dec 20 12:33:05 f18aio kernel: [ 4749.115677] ata1: EH complete
Dec 20 12:33:06 f18aio kernel: [ 4749.966412] ata2: soft resetting link
Dec 20 12:33:06 f18aio kernel: [ 4750.120449] ata2.00: configured for MWDMA2
Dec 20 12:33:06 f18aio kernel: [ 4750.120952] ata2: EH complete
Dec 20 12:33:08 f18aio kernel: [ 4752.177808] ata1: soft resetting link
Dec 20 12:33:08 f18aio kernel: [ 4752.330692] ata1: EH complete
Dec 20 12:33:09 f18aio kernel: [ 4753.183308] ata2: soft resetting link
Dec 20 12:33:09 f18aio kernel: [ 4753.337768] ata2.00: configured for MWDMA2
Dec 20 12:33:09 f18aio kernel: [ 4753.338555] ata2: EH complete

In engine.log
2012-12-20 12:33:03,939 INFO  [org.ovirt.engine.core.vdsbroker.vdsbroker.ValidateStorageServerConnectionVDSCommand] (ajp--127.0.0.1-8702-2) [73e31316] START, ValidateStorageServerConnectionVDSCommand(HostName = local_host, HostId = 6ae6e471-d46b-48f5-8b0f-6f5cc20b251e, storagePoolId = 00000000-0000-0000-0000-000000000000, storageType = NFS, connectionList = [{ id: null, connection: f18aio:/ISO, iqn: null, vfsType: null, mountOptions: null, nfsVersion: null, nfsRetrans: null, nfsTimeo: null };]), log id: f20d993
2012-12-20 12:33:03,944 INFO  [org.ovirt.engine.core.vdsbroker.vdsbroker.ValidateStorageServerConnectionVDSCommand] (ajp--127.0.0.1-8702-2) [73e31316] FINISH, ValidateStorageServerConnectionVDSCommand, return: {00000000-0000-0000-0000-000000000000=0}, log id: f20d993
2012-12-20 12:33:03,952 INFO  [org.ovirt.engine.core.bll.storage.AddStorageServerConnectionCommand] (ajp--127.0.0.1-8702-2) [73e31316] Running command: AddStorageServerConnectionCommand internal: false. Entities affected :  ID: aaa00000-0000-0000-0000-123456789aaa Type: System
2012-12-20 12:33:03,954 INFO  [org.ovirt.engine.core.vdsbroker.vdsbroker.ConnectStorageServerVDSCommand] (ajp--127.0.0.1-8702-2) [73e31316] START, ConnectStorageServerVDSCommand(HostName = local_host, HostId = 6ae6e471-d46b-48f5-8b0f-6f5cc20b251e, storagePoolId = 00000000-0000-0000-0000-000000000000, storageType = NFS, connectionList = [{ id: 309f07eb-ae33-4892-9415-a21c774a89e2, connection: f18aio:/ISO, iqn: null, vfsType: null, mountOptions: null, nfsVersion: null, nfsRetrans: null, nfsTimeo: null };]), log id: 3255e846
2012-12-20 12:33:03,996 INFO  [org.ovirt.engine.core.vdsbroker.vdsbroker.ConnectStorageServerVDSCommand] (ajp--127.0.0.1-8702-2) [73e31316] FINISH, ConnectStorageServerVDSCommand, return: {309f07eb-ae33-4892-9415-a21c774a89e2=0}, log id: 3255e846
2012-12-20 12:33:04,021 INFO  [org.ovirt.engine.core.bll.storage.GetExistingStorageDomainListQuery] (ajp--127.0.0.1-8702-2) START, GetExistingStorageDomainListQuery(org.ovirt.engine.core.common.queries.GetExistingStorageDomainListParameters@705c0fb1), log id: 6e3f186a
2012-12-20 12:33:04,024 INFO  [org.ovirt.engine.core.vdsbroker.vdsbroker.HSMGetStorageDomainsListVDSCommand] (ajp--127.0.0.1-8702-2) START, HSMGetStorageDomainsListVDSCommand(HostName = local_host, HostId = 6ae6e471-d46b-48f5-8b0f-6f5cc20b251e, storagePoolId=00000000-0000-0000-0000-000000000000, storageType=NFS, storageDomainType=ISO, path=f18aio:/ISO), log id: 1eb50b8c
2012-12-20 12:33:07,156 INFO  [org.ovirt.engine.core.vdsbroker.vdsbroker.HSMGetStorageDomainsListVDSCommand] (ajp--127.0.0.1-8702-2) FINISH, HSMGetStorageDomainsListVDSCommand, return: [52f15c20-82ef-4fe6-8609-9d43fa6ce72d], log id: 1eb50b8c
2012-12-20 12:33:07,163 INFO  [org.ovirt.engine.core.bll.storage.GetExistingStorageDomainListQuery] (ajp--127.0.0.1-8702-2) FINISH, GetExistingStorageDomainListQuery, log id: 6e3f186a
2012-12-20 12:33:07,207 INFO  [org.ovirt.engine.core.bll.storage.RemoveStorageServerConnectionCommand] (ajp--127.0.0.1-8702-2) [a59e1de] Running command: RemoveStorageServerConnectionCommand internal: false. Entities affected :  ID: aaa00000-0000-0000-0000-123456789aaa Type: System
2012-12-20 12:33:07,211 INFO  [org.ovirt.engine.core.vdsbroker.vdsbroker.DisconnectStorageServerVDSCommand] (ajp--127.0.0.1-8702-2) [a59e1de] START, DisconnectStorageServerVDSCommand(HostName = local_host, HostId = 6ae6e471-d46b-48f5-8b0f-6f5cc20b251e, storagePoolId = 00000000-0000-0000-0000-000000000000, storageType = NFS, connectionList = [{ id: null, connection: f18aio:/ISO, iqn: null, vfsType: null, mountOptions: null, nfsVersion: null, nfsRetrans: null, nfsTimeo: null };]), log id: 68961755
2012-12-20 12:33:10,326 INFO  [org.ovirt.engine.core.vdsbroker.vdsbroker.DisconnectStorageServerVDSCommand] (ajp--127.0.0.1-8702-2) [a59e1de] FINISH, DisconnectStorageServerVDSCommand, return: {00000000-0000-0000-0000-000000000000=0}, log id: 68961755
2012-12-20 12:33:12,729 INFO  [org.ovirt.engine.core.bll.LoginUserCommand] (ajp--127.0.0.1-8702-2) Checking if user admin@internal is an admin, result true
2012-12-20 12:33:12,729 INFO  [org.ovirt.engine.core.bll.LoginUserCommand] (ajp--127.0.0.1-8702-2) Running command: LoginUserCommand internal: false.
2012-12-20 12:33:12,739 WARN  [org.ovirt.engine.core.bll.GetConfigurationValueQuery] (ajp--127.0.0.1-8702-2) calling GetConfigurationValueQuery (ApplicationMode) with null version, using default general for version
2012-12-20 12:33:12,740 WARN  [org.ovirt.engine.core.bll.GetConfigurationValueQuery] (ajp--127.0.0.1-8702-2) calling GetConfigurationValueQuery (VdcVersion) with null version, using default general for version

Thanks,
Gianluca