Transfer origin caller id when forwarding calls


I’ve just installed the current trixbox-Version; calling from and to outside via sipgate (germany) works well; internal calls too.

But I have set up an ring group with an external member (mobile phone)

When calling to this ring group, the CallerID of my sipgate-Account is shown and not the origin-callers-id.

Sipgate allows me to set the caller id, but how can I set it “dynamically” for forwarded calls?

Any ideas?