Hooking up the RC-4 to a FEZ Cobra

[Spark]

I wanted to clarify a couple areas before proceeding and possibly blowing out my RC-4.
The FEZ Cobra has 3.3V output pins which include 4 dedicated hardware TX and RX ports.  I am slightly confused on how I will hook this up.   So I have a few questions maybe someone can answer for me.

The description states:
Note
The RC-4 gets power from the host controller (Prop-1, Prop-2, or Prop-SX) and, therefore, must be placed first in a chain of EFX-TEK accessories connected to a controller as the other devices (AP-8, DC-16, FC-4) do not route +5 VDC power through.

Please correct me if I am incorrect in my understanding.

Normally, the RC-4 would hook up in the following manner with the 3 wire servo:
GND - Black
PWR - Red
Signal(RX&TX) - White 

Servo to RX and TX hardware pins would normally be (for serial connections):
GND - Black
RX - Red
Signal(TX) - White

My understanding is that RX and TX under the Parallax AppMod bi-directional communications protocol, run on the same wire (white) and the (red) wire, which would normally be the RX is used for the +5V power.  The TX and RX (send/receive) are controlled at the logic level.  If this is true, then on the FEZ Cobra, it would hook up similar to an Arduino and would need something like a 4.7K resistor between the RX & TX hardware pins.  White would go to the TX pin, red to a 5V power pin (may need a step up to get from 3.3V to a regulated 5V like this Pololu 5V Boost Regulator NCP1402 to provide power)

Questions:
If the RC-4 get its power from the +5V, then there is no need to provide power via the plug?  Or is it best to keep the power for both the controller and the RC-4 separate?  Or could be used either way ...  If I choose to power via the plug, I assume the (red) +5V wire does not need to be connected. 
Given this is true above, Will the 3.3V signal be enough to pass the AppMod commands through the signal wire or do I need to use a regulated step up or boost to get the 5V. 
I think it looks like straight UART is the simplest to use off the FEZ Cobra and just write the commands out to the RC-4.
Thanks for your help on clarifying this. 

[JonnyMac]

If you have one of the newer RC-4s with power plug you can use that; that version actually defaults to the plug (you must cut a jumper to get power through the serial interface).

On the serial thing; it should work fine with a 4.7K resistor connected between your RX and TX pins; and make sure you connect the serial connection of the RC-4 to your RX pin.  The 3.3v output should be fine as this is well above the 1.4v TTL threshold used by the SX chip.  Just keep in mind that anything you send to the FC-4 will also end up in your receive buffer so you need to filter that out in the application.

Your connections will be simple: one wire for the serial comms, and ground.