Problem interfacing VP530 with ClearOne Videoconference system

[Mauro]

Hello everybody.
We would like to connect our Yealink VP530 phones to our "ClearOne Collaborate Room SD" Videoconference system (it does support SIP mode, other than its main H.323 mode).

Even if they are connected in the same subnet, and we think we have enabled all the codecs available in both configs, and we have done a SIP "direct" call (specifying destination IP instead of its internal number, to do not pass through the PBX), the thing does not work as expected.
The videoconference system sees and hears the videophone, while the videophone only hears, but cannot see the image from the videoconference system.

Any ideas? Has someone a such environment working?

Some infos about the videoconference system:
http://www.clearone.com/products_collaborate_room_sd
http://www.clearone.com/uploads/resource...otes-0.pdf

[Yealink Support]

Can you ask your distributor for help?
Then supply syslog level 6, config.bin and pcap for two callers.
How to Get the Correct Syslog, Config.bin and Trace