I paid an A/C repair place to replace the RCV. Success!
Yes, the valve can be replaced without removing the compressor. Mine was only held in by one hex bolt. I could have done it myself if I had the equipment and knowledge needed to evacuate and recharge the system.
June 21, 2012 I called Polar Bear, Inc, Ft. Lauderdale, FL (954)-463-6610 and ordered their part number PXE13-16 CONT VLV EARL with a price of $61.54, plus tax and shipping total of $79.69.
June 23 of 2012, I paid Ice Cold Auto Air in Clearwater, FL $36 plus tax to replace the defective valve with the valve that I supplied them. They charged me another $90 plus tax to evacuate and then recharge the system. They warned me that there would be no warranty on the repair, as I was supplying the part and dictating the procedure.
My 2006 Jetta A/C has performed flawlessly since then, here in Florida.
Your results may vary.
Can you replace the valve without removing the compressor?