I think this is a half solution to that problem, the best solution is that communicator checks/read the forward setting from the PBX via CSTA.
The problem is right now will Communicator overrule forward setting on the phone.
<GetForwarding xmlns="http://www.ecma-international.org/standards/ecma-323/csta/ed3">
</GetForwarding>
source:
http://www.ecma-international.org/publications/files/ECMA-TR/TR-087.pdf
Microsoft KB960424
You cannot prevent Office Communicator 2007 from controlling the call forwarding settings. In some scenarios, Office Communicator 2007 will overwrite the Private Branch Exchange (PBX) forwarding settings. This causes you to lose some important calls.
To resolve this problem, install the update that is described in Microsoft Knowledge Base article 957465. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
957465 (http://support.microsoft.com/kb/957465/ ) Description of the Communicator 2007 hotfix rollup package: December 19, 2008 This update provides a new policy. This policy disables the call forwarding settings from Office Communicator for a Remote Call Control user. Office Communicator no longer controls forwarding settings on the PBX after this policy is applied. To do this, follow these steps:
Click Start, click Run, type regedit, and then click OK.
Locate and then click the following registry subkey:
- HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Communicator\
- On the Edit menu, point to New, and then click DWORD Value.
- Type DisableRCCForwarding, and then press ENTER.
- Right-click DisableRCCForwarding, and then click Modify.
- In the Value data box, type 1, and then click OK.
- Exit Registry Editor.
