Blind transfer over DPNSS problem

[paynep]

Hi,
Have seen recent thread where Qsig seems the way forward, but have a slightly different prob:

Blind transferred calls between an Opt 11c extension and a Siemens DX3000 extension won't revert to the originator if unanswered.
It works fine in same environment (ie DX to DX or Meridian to Meridian transfer) but not over the DPNSS link.
Both system maintainers claim their switch and config is fine and it must be the others problem - am I getting the runaround or is it a known interworking problem?

I should be able to get the 11c config shortly, is there anything obvious to look out for?

Thanks, Paul