I've developed an Excel Addin with several UDFs. Everything's fine until my
users want to pass their spreadsheets to other people that don't have my
addin installed. They get #Name in the cells that reference my UDFs. How do
my customers replace the references to my UDFs with their results? These UDFs
could be part of another formula.

e.g = MyUDF(10 * Sum(A1:A10) * MyUDF(B2))

The only solution that I can think of at the moment is to a do a global copy
& paste value, but these loses all formulae.

I know that Excel can replace parts of a formula with its value whilst
editing it. Can this be done programmatically?

Thanks

Dave