Call Waiting Tone/Beep missing during active calls

[vancomycin]

Hey - noticed this on two 6.5 CDMA ROMs I have tried - sharkie / lead ROM CDMA for sprint.

While I am on the active phone call - I will receive an incoming call (call waiting) - I will not hear any sound / tone / beep alerting me there is another call coming in. I will see the end/send key "light up" and that the incoming caller's information displays - but NO TONE.

This is pretty frustrating - can't find where I need to go within phone settings to enable this.

*** I also threw all the stock TP2 default sounds into the /application data /sounds folder

*** Went to Sounds/Notifications > notifications tab - but there is no drop down menu for "call waiting"

*** If I scroll through the sound list - I see the "call waiting tone" and can play it -

I had a friend call me from a landline to test this out while on their mobile. Still no incoming call waiting tone when on the initial active call.

looked at registry : HKEY_CURRENT_USER\ControlPanel\Sounds\CallWaiting
and sound set to "callwait.wav" , Script "apr" , category "incall"

p.s. - I have system and ringer sounds set to maximum. All other notifications, incoming ring tone, data connection, new sms, voicemail have been working.

What to do?