Now, i'm able to login to the dwa, but there's nothing to do with the FQDN, because the value for that field is already in FQDN format before i can login to the dwa.
What i did is change the http authentication field to "single server" instead of "Multiple server (SSO)". After that, the problem is solved.
But i'm encounter another poblem after login and enable the IM on the preference, the IM button showing a gray dot with the lable Disconnect, and there's no option to login IM after click on the IM button. I have go through the forum, and there's a lot of similar case, it was something related to the dwa7 template, and a lot of these issue stil don't have solution, or the solution provided dosen't fix my problem.
I wonder whether this issue has be report to IBM support, and whether there's standard solution provided by IBM.