2 vu's and 2 remotes question

Hi all, I have 2 vu boxes, a Duo2 and a Duo4kse , both are using the later remotes. I have worked out that the standby and ok button puts the handset into program mode. My question is how do I change one of the remotes so they don't clash. Currently the code is 00002 on both boxes. I tried to use the remote controlcodeplugin but it doesn't seem to do anything. Thanks