Primus 1000 FMS brain damage

Today I departed out of RIL as a passenger on a Citation V Ultra being
flown under Part 135. Despite the winds and terrain favoring a
departure from runway 26, we departed runway 8. One of the consequences
of this was that we needed a 5500 foot ceiling, which we darn near
didn't get and we almost got stuck there.

When I asked why they departed runway 8 instead of 26 (whose departure
minimums require only a 3500 foot ceiling) I was told that the Honeywell
Primus 1000 FMS could not be programmed to properly fly the Squat 1
departure (http://204.108.4.16/d-tpp/0801/06741SQUAT.PDF). In
particular, the procedure requires that the plane fly to YIRDU
intersection before turning towards SQUAT, but the Primus 1000 always
interpolates its turns (i.e. it would start turning towards SQUAT
slightly before reaching YIRDU), and this cannot be overridden.

This all sounded a little farfetched to me. Leaving aside the fact that
it's only a 15 degree turn, I don't understand how any IFR-certified GPS
(let alone one that they would install on a freakin' jet) could not
properly fly a published GPS departure procedure.

Can anyone here shed any additional light on this situation? Is this
really true, or did I get told a tale?

Thanks,
rg