Trying to rewrite URLS getting endless loop, the rewrite code looks fine?, going nuts

Hey all,

I need to make a what should be simple rewrite urls from

Productname-123456.html

to

Productname-p-123456.html

So for an oscommerce store to switch to ultimate SEO urls format.

Here's what should work but isn't

RewriteRule ^(.*)-([0-9][0-9][0-9][0-9][0-9][0-9])\.html$ $1-p-$2.html [R=301,L]

Code (markup):

The probllem is right after the $2

If I put another character there ie

RewriteRule ^(.*)-([0-9][0-9][0-9][0-9][0-9][0-9])\.html$ $1-p-$2e.html [R=301,L]

Code (markup):

Notice the "e"

Now it works but I would now have an "e" there.

Please how should I pursue this? Am I supposed to wrap the $2 in something?

Thanks

 

nobody? Really need some input.