Thinking about it i had to do the same with a OS7200S on a site to get it to connect (xchange 2.3).

I can't remember if my office OS7200 already had that set before i upgraded to 4.70.

This is probably samsung's fault for not telling mondago about all the changes in 4.70 software.

Xchange has been supported on samsung OS7000 systems since 4.21 software.