Goldensyrup,
The Haynes manual procedure for replacing power steering fluid provides a draining procedure, then a top up process. If you are changing from non-synthetic to synthetic, I would use this procedure. Although, my recommendation is just use the same fluid - which means returning to Saab (again) and advising them of the mix up with your car, plus checking their computer records.
I changed/replaced my synthetic (1998 car) fluid last weekend, using the pump in/out procedure defined here..:
http://www.saab9000.com/procedures/suspension/steeringflush.php
After jacking front of car up, the following is additional advice, further to the info in the above link..:
I used 4 feet of clear reinforced petrol pipe (appox 12 mm inside diameter).
NB: This pipe was approx the size of standard hose pipe.
A 12 inch piece of black silicon hose (4mm inside diameter) plugged nicely into this clear hose, and the other end into the end of the Saab 9000 power steering return feed pipe. I just nipped up the jubilee clip on the connection to the Saab 9000 return feed hose, but no other clip was necessary. This 12mm piece of reduced diameter pipe may help to reduce the flow when the engine is running.
The end of the 4 foot clear hose goes into a 5 litre used oil (or equivalent) container to collect the old power steering fluid.
To bung the power steering fluid return pipe inlet, just use 4 inches of clear reinforced petrol pipe (same diameter as above), with a piece of wood dowel (or equivalent) plugged into the end. No jubilee clips required to hold in situ.
Once engine is running, the steering wheel needs to immediately be turned from lock to lock quite quickly, in order to ensure the old fluid is pumped out. My 'helper' managed 4 complete lock to lock turns, whilst I kept the reservoir topped up using 2.5 litres of new fluid. I retained 0.5 litres to top the system up after stopping the engine, connecting the return feed back up and then - with engine still off - winding steering wheel back and forwards slowly to dispel all air bubbles. Then using 0.3 litres to top reservoir up to Max level, with 0.2 litres spare fluid.
I found a total of 2.8 litres was sufficient to purge the system of 10 year old fully synthetic fluid, although the Saab9000.com reporter (see link above) recommended 4 litres for non-semi-synthetic fluid replacement in older cars.
Overall, simple process, and P-S-pump remained filled with fluid, helping to prevent damage - which may be a better process than the Haynes manual drain-refill-rotate steering wheel to expel air bubbles- all with engine off-approach.
HTH's,
Paul