Could VNotes or OTHER application record the conversation when talking with someone on the iphone?

When my 1st install the VNotes using the installer. I can't record my voice, but when I call my voice mail, then I go back to the VNotes while I can hear the Voice mail, the VNotes can record the sound from voice mail but not my voice when I try to talk at same time.

I uninstall the VNotes then install the VNotes 2nd time, I can record my voice normally this time, but can't record the sound while calling the voice mail.

Any application can record the conversation on the iphone?

Thanks.