procmail score and more

My site has been suffering from too many SPAMs that typically contains 
many embeded "http://" links (hyper mail).  I made the following recipe to 
filter them if more than 10 http links found in a mail body:

:0 fbw
* > -10^0
* 1^0 http://
| formail -i "ProcSpam: <-------- too many 'http' found ---------->"
   :0 a:
   HTTPam

but it's not catching them. I humble that probably the procmail score
count matches on line by line basis and the hyper mails often have lines 
clumpsed into one or few lines (is this the case?)  Therefore I wrote a 
few lines perl code to count "http://" which works fine on command line.

I know how to feed the mail to and trigger my perl program -- I need 
advice on how (in procmailrc) to get the returned counts and set a simple 
number comparison recipe for a decision?

Thanks in advance!

Zhiliang