user_prefs read from somewhere else

[Alex Thor]

Hi there!

Is there a way to convince spamassassin to read the *user_prefs* file 
not from ~/.spamassassin/  but let's say /var/mail/<name>/.spamassassin/ ?

I use sendmail with spamassassin milter, whereby spamass-milter starts 
with 
-u defaultuser

Thanks in advance!
Alex