no ringback from cisco call manager phones when calling from hipath

[noidatech]

im facing a problem

site A ( siemens hipath ) is running Qsig with site B (avaya g3r )

siteB ( Avaya) has Qsig trunk with site C ( cisco call manager)

site A ( siemens) and site C ( cisco call manager) are not connected directly .

Site B( avaya) does call routing if site A wants to talk to site C

site A( siemen hipath) stations when calling to site C ( cisco call manger) call connects and completes but there is no ringback, caller only come to know abt call completion when the far end user picks the phone and answers.


site B( avaya) users when calling to site C( cisco call manager) everything works fine


anybody knows what could be the issue and how to fix it, im sure we dont have to change anything on call manager , it should be surely something on siemens hipath...but no clue

any help will be hihgly appreciated

thanks in advance