Thank you Richard!
I see you too got the temperature conversion covered but not pressure and/or humidity which is where I'm currently got stuck. Haven't done anything with it for a couple of days, perhaps I'll get back to it - or I won't.

Ioannis,
Yes, I know about the N-bit routines and if I don't succeed in getting the "native" 32bit fixed point routines they do show in the datasheet to work I might try with N-bit but I suspect it won't actually make it much easier.

Right now, my guess is that the problem has to do with me niot be able to "translate" their mix of signed and unsigned numbers of various bit lengths into PBP lingo.
I'm reading the compensation values from the sensor and "manually" casts them into LONGs in order to make them signed. But then not all of them are supposed to BE signed but in PBP all longs ARE signed and it becomes a mess quite quickly. It would be nice to have set of input values with a known output so one could split the calculation in steps and figure out where it goes wrong.

/Henrik.