i only get two buttons when receiving calls - answer and decline, and have never seen a "send" button. who was calling you when you saw that send button (someone in your contacts, your cell phone carrier, a businesss)?
it was no one important, a girls cell. I forget if I was doing something before the call. It was like a little extra button above the regular in-call options (keypad, speakerphone, etc) I can't believe no one else has seen this.