Dspam

I have an install of postfix with dspam.
Everything is working good and dspam is picking spam out very nicely.
Problem I have is that I am having train everything by hand.

I have tried to setup 2 global aliases spam@mydomain.com and
notspam@mydomain.com.

Problem is everytime I forward spam to the address the dspam ID appears
to get changed to the dspam ID of the alias i.e. spam@mydomain.com.
It it not retaining the original message dspam ID.
This is driving me nuts.

Any help would be muchly appreciated..

Regards
Col