its rather tedious to create 1 from scratch

I can't tell since I have no idea what Cadstar is (I use Orcad), but, for uCs and such, I prefer to make my own symbolic devices, simply because locating ports etc to fit the app makes for a much more readable schematic. E.g. if p1 is input and p0, p2, p3 are outputs, it makes sense to craste a device with p1 on the left and the other ports on the right.

Eroik