Call Forwarding with Pin Sets enabled - caller is asked to enter pin

Hi Everybody,
This is the problem.

I have a site with about 50 handsets.
Many of the extensions have their own DID.
This works fine.
You call the person DID number and their extension rings and the person picks up the handset and answers the call.
All cool so far.

I have enabled PIN SETS to track outbound calls for billing purposes. No problem with this either.

HOWEVER, if the employee leaves their desk and diverts their extension to their mobile phone using Call Forward feature, the inbound caller is asked to enter a PIN.

I understand why this is happening. Because the forwarding of the inbound call to the employees mobile is regarded as a new (2nd) outbound call and hence should be subject to scrutiny by requesting the caller to enter a PIN code.

The only problem is that it is not practical to provide an employees pin code to everybody who may need to speak to them.

Does anyone know a way around this problem.

Thanks in advance - I need some help here !!!!!!!!!