php5 downgrade

Hello,
i just installed php5.2 from cvs updated pkgsource. Now I
realized that this
was really a bad idea and I would like to downgrade to 5.16.
I tried
serveral cvs commands but i had no succsess to get the older
version of php
into my /usr/pkgsrc/lan/php5 directory. I hope someone can
help with this.

Tia

Arne