I'm configuring a softphone (Zoiper) for our upcoming vacation. I seem to be having an issue interacting with IVR systems. I need to chose one of the following:

DTMF RFC-2833
DTMF SIP INFO
DTMF Inband

and, I'm fairly certain I tried all three without success. I'm open to using a different softphone (e.g. X-Lite).

Any kind of feedback would be appreciated.