I have a library XLA file where I keep custom functions I've written and use in
multiple spreadsheets. The XLA file resides in my XLStart subdirectory and all
works as I would expect it to. I can call the functions from any spreadsheet cell.

My current problem arises in that I'd like to call one of the functions from
within a VBA macro. Somehow I'm unable to figure that out. If I try to call it
normally:

X = MyFunction(Y)

I get a compile error "Sub or Function not defined". So then I tried:

X = Application.WorksheetFunction.MyFunction(Y)

and get an error "Object doesn't support this property or method". Various
other attempts to point VBA to find the custom function all fail.

What's the key? Thanks.

Bill