In 97-2003, in the CF dialog change Cell Value Is to Formula Is and enter a
formula that evaluates to True/False.
In 2007+, in CF rules, click on "Use a Formula to determine which cells to
Format"

Enter your UDF in the normal way in the CF formula

Experiment with Relative & Absolute references, there are significant
differences in the way they work particularly when it comes to copying cells
with CFs.

Regards,
Peter T

"Faraz Ahmed Qureshi" wrote in
message ...
Any guidance as to how to have a UDF in an addin be declared/registered
etc.
so as to be used like all other usual/normal functions? like be
autocompleted
upon partial entry, arguments be displayed in the supertip and be capable
to
be used in the Conditional Formatting and other features?

--
Thanx in advance & Best Regards,

Faraz!