[Serusers] fields To/From

[Piccari Gianluca]

Hi all,
 i have a big problem... i need to parser information in Header field From() and eventually add or delete part of info in Header field TO.

For istance: if i(n From field there is '55') 
                  add ('55' in To field).

I don't have familiar to SER (i have started to study it last week (: ) and i likr e to know if it is possible to do it using SER's method without
change the source code ....
thanks for your help