Have you seen this from MoreBeer?
http://morebeer.com/themes/morewinepro//kegging.pdf
"Saturation Over Time:
The principal of this method is simple: If you leave constant pressure on the beer it will absorb the Co2 until the pressure pushing down on the beer equals the internal pressure of the gas dissolved in the liquid.
Depending on the temperature and Final Gravity (F.G.) of the beer, beer will usually take an average of 510 days to stabilize.
1. Hook the Gas-In Quick Disconnect to the Gas-In Body Connect and turn the gas on.
2. Adjust your regulator to the desired PSI and let the beer sit at this pressure for 710 days.
3. You can test your beer by pulling a pint off of the keg after 57 days.
4. If the beer is under-carbonated to your taste, let it sit for another 13 days, testing periodically as necessary.
The great thing about carbonating over time is you give your beer a period of cold aging while avoiding any chances of over carbonating, which can lead to excess foam and make serving beer very difficult. Although this method takes longer than the others, this is by far the easiest and least involved method."
Drinking = Lucky Red ale, Blonde Hag ale, Amber Tomahawk ale
Secondary = Baby shoes IPA