i do all my bracket design on an even more expensive CAD system than yours (Creo 5) , and yet, still simply measure everything with a caliper off the caliper itself
sounds like you have to have that bracket right now, otherwise ....
In building bikes, patience is paramount....
I've seen form other post that you are not that receptive to other peoples friendly advice, nevertheless, here is mine: Grimeca used to do many "Brembo replica" calipers like the P08 and P05 look alikes that have the same dims and between holes distance. It's a good bet they did also a P108 look alike and i've come across Grimeca Pdf catalogs that have complete caliper drawings, dig the net a bit, you might find it.
Will dig my hard disc too, will give you a copy if you promise to be nice to us hipo sohcers