VM_caller id when a call is transferred to voice mail

We are using Asterisk as a voice mail server and Call manager as our
IP PBX. SIP trunk is used between the Cisco Call manager and Asterisk.

When the receptionist receives a call, she can transfer the call (Normal call transfer using Cisco phone) to the voice mail using a special number. The caller can now leave a
message. However, when she does that, the caller id on the voice mail
is her caller id instead of the original caller.

I made some capture and I can see that call manager sends re-invite with the the caller ID of the original caller in the VIA header.
Is there a way of set the VM_caller_ID at the reception of the re-invite?

Here is the configuration of the extensions.conf

exten => _7002XXXX,hint,SIP/${EXTEN}
exten => _7002XXXX,1,set(LANGUAGE()=fr)
exten => _7002XXXX,2,SetVar,extension=${EXTEN:4}
exten => _7002XXXX,3,ringing
exten => _7002XXXX,4,Voicemail(u${extension}@default)
exten => _7002XXXX,5,Hangup()

Thanks and regards

Richard