Semi-attended transfer

Hello. Can i use semi-attendend transfers with asterisk?

Now i have got
Asterisk 1.2.22
linksys pap-2 (ext 2035)
Linksys SPA-942 (ext 2001)
Linksys SPA-942 (ext 2002)


Call from 2035 to 2001 -> 2001 answer -> press xfer button -> call 2001 to 2002 -> 2002 ringing -> press xfer button -> 2002 ringing off (missed call) -> wait ~1-2 sec (###) -> 2002 ringing -> 2002 answer -> now the 2035 can speak with 2002 (transfer complete successful)

But there is problem. If 2002 will answer in the period ### - the transfer will fail. In this period 2035 listen MOH and after that can listen busy signal.

I have planned to use SPA-942 as receptionist’s phone but it is impossible with this bug.

Is there some way to fix this problem? I won’t use transfer from “features” and i won’t use blind transfer at all. I can show sip debug if it can help to resolve.