java mapping?

Hi guys,

from all the topics I've seen about mapping on XI, the only ways are doing it by message mapping, JAVA mapping, ABAP mapping or XSL.

The thing is, if there is a lot of work done by an client company in VB which is responsible for the mapping, is it possible by any means to use those methods?Compiling the code and place them on a zip, is it possible?Or am I obliged to write the same code in JAVA or ABAP? The company is interested in not wasting time redoing the same code, is it possible?

Thank you guys.