Implementing Provider - Pblm with username

[Pradeep]

hi,
Im implementing my own provider for personalizing web parts by
overriding the personalizationprovider base class.. The problem is the
usernames that comes as arguments with the personalizationblobs are the
windows login usernames.. But i want these names to be taken from a
database / session variable / query string..! How can i do this..?
Please be quick...
Thanks in advance
Pradeep