Spammer with attachment that bypasses spamassassin

[George Papamichelakis]

Hi all


I Have issue with one spammer that due to fact that  he includes some 
pdf file in his email

bypasses the blacklist and his email gets delivered to all addresses 
that he has from the domain.

Can I somehow force mailscanner to not bypass this particular sender  
due to message size ?

I use mailscanner 5.0.2 with postfix  on a debian machine and mailwatch 
1.2.10 web interface.


thanks in advance

GP