T20P + Failed transfering calls

[tic.oxipira]

Good morning everybody.
I'm trying to transfer received calls from internal phone to another one, but without success!
I would like to know if you guys can help me with it.

Scenery:

PABX: Panasonic NCP1000
Phone1 - 977: Generic analogic model
Phone2 - 988: Yealink T20P
Phone3 - 976: Generic analogic model
Infrastructure: The Phone2 is connected in the LAN by the switch so did the PABX. The phone isn't connected directly in the PABX card!

Situation:

1 - Phone1 calls Phone2 - OK
2 - Phone2 receives the call and transfer to Phone3 by whatever the default transfer methods - OK
3 - Phone2 presses "transfer" button and the call isn't transfered to Phone3.

[Karl_Yealink]

1. The firmware of the phone?
2. How many phones do you have? All of them have this problem?
3. Both the attended transfer and blind transfer can't work.
When you press the ok button to complete the transfer, the transfer is attended transfer.
When you press the transfer button to complete the transfer, the transfer is blind transfer.