USSD via AT hangs up Green Button on N95, N82

[Avis]

We have sample code for getting prepaid balance by USSD request.
It works good on all 9.x devices except N95 and N82. After this code executing on that devices Green Button begin
to work in unnormal way: user can not dial from Contacts or from Call Log. Device just don't respond on Green Button pressing. Normal work returns only after device reboot.
Is there any way to fix this bug or bring Green Button back to life without reboot?

User::LeaveIfError(StartC32());
RCommServ commServer;
CleanupClosePushL( commServer );
User::LeaveIfError(commServer.Connect());
_LIT(KCsyName, "dataport");
User::LeaveIfError(commServer.LoadCommModule(KCsyName));
_LIT(KDataPort, "DATAPORT::1");
RComm commW;
CleanupClosePushL( commW );
User::LeaveIfError(commW.Open(commServer, port, ECommShared));
TBuf8<128> atCommand;
atCommand.Append(_L8("AT+CUSD=1,\""));
atCommand.Append(_L8("*105#"));
atCommand.Append(_L8("\",15\r\n"));
TRequestStatus callStatus;
commW.Write(callStatus, atCommand);
User::WaitForRequest(callStatus);
CleanupStack::PopAndDestroy( &commW );
User::LeaveIfError(commServer.UnloadCommModule(KCsyName));
CleanupStack::PopAndDestroy( &commServer );

[symbianyucca]

I would try making it with real active object without the WaitForRequest(), then you could have more control on it, as well as it would be less likely to hang, might also solve the problem you are having.

[Avis]

Well, this is just an example. And it works OK, and app closes correctly with ext code = 0.
There is no hang up's.
And in real app I use active object - getting USSD answers etc.
All work OK, except this bug with Call Button (green key).
And this bug appears only on N95 and N82 devices.