Actually that is not the Problem I had in mind, for this problems by the way all users are affected and you never get the system working. but using CRM you should have at least the mentioned fields in the Call Attached data anyway.
I think we fixed the issue with either SP 6 Patch 1 including some Hotfix or by installing SP 7.
At least for those customers we no longer experienced this issue. I am sorry I cannot remember which version exactly solved this.
From experience so far I would highly recommend updating to SP 7 anyway.