regexp

[andu]

I need some help with matchChunk(). Here's the problem, I need to parse 
html pages for a certain chunk and replace it with an other. Unfortunately 
I cant use the good old "replace x with y in z" because the chunk sometimes 
is on one line other times on many.
Here's an example:

        <p><font face="Arial" size="2"><b>Welcome
          <!user-name>

          to our site</b></font> </p>

I want to replace "Welcome <!user-name> to" with "This is", for example.
 I've spent hours trying to find the right matchChunk() expression given I 
know the first (Welcome) and last word (to) of the chunk but without 
success, I can only get one of them at a time. Thanks in advance for any 
suggestions.

Regards, Andu Novac