Hello experts,

we where testing IAD2432 with SIP and it seems we can not make it to support hook-flash functionality. When I dial first number and press flash button I get a second dial tone and first phone conversation is on hold, after dialing a second number when I press flash button I get a third dial tone not a 3-way add hock conference as with traditional PBX like feature and first call gets dropped.

Bellow is the documentation I used to configure those features with SIP:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123cgcr/vvfax_c/callc_c/sip_c/sipc1_c/centrex.htm#wp998956

http://www.cisco.com/en/US/products/ps6441/products_feature_guide09186a0080783aba.html

Any suggestion on making this working will be welcome. Thank you in advance.

The config is attached.