Problem with alternate GWIA Agent

[markusherbert]

I have a GroupWise 8.0.1 System based on NetWare 6.5.

My MainDomain is on a NetWare Cluster, the GWIA'a are on seperate Domains.
So my Structure looks like this:

MainDomain on Cluster Server
- Postoffices
SEKDOM1 on Server FS002
- GWIA1
SEKDOM2 on Server FS003
- GWIA2

All domains are connected via TCP/IP and are working fine.
When I edit the properties of MainDomain -> Internet Adressing I'm able to set the Internet-Agent for outgoing SMTP/MIME messages,
but I'm not able to set the alternate Internet-Agent because it is greyed out.

Does anyone has a solution for this problem?