Samsung Epic 4G :: Listen To Music And Take Calls In Car

First off I apologize if this is answered elsewhere. I am a newbie and this is my first smart phone.I love the Epic everything works perfectly after I exchanged the first one for the back button issue.My question is I am listening to streaming radio in the car, through a cassette adapter that is plugged into the headphone jack on the epic and everything is cool. when I get a phone call - The radio goes off and I can accept the call, however here is the problem.When I answer the call I can hear the caller through the car speakers (makes sense) but they cannot hear me, I try pressing the speaker button and still they cannot hear me. I think the Samsung programmers have assumed that I have headphones plugged in with an attached mic and not a straight output jack.How do I answer calls in this situation?I am not willing to unplug the cassette adapter when cruising down the interstate at great speed.Is there a setting or a device (bluetooth or other?) that will enable what I need to accomplish.CLOSED - I just bought a $10 cable with a built in mic from Best Buy.