Juan,
There's an example of doing this in this article by Calvin Hsia of Microsoft:
http://www.activevfp.com/dev/dna08.htm
>Hi
>
>I have been reading VFP and Excel help system in order to add optional functions in excel but I can't get sucess at all. This is what I've done:
>
>1. I Created a Custom Olepublic class with an example Method to multiply numbers. I want further to seek and return values from VFP tables.
>
>2. In Excel, I went to Tools - Add-Ins - Automation and I selected MyServer.MyClass from the available servers list.
>
>3. But I get this error:
>Cannot find Add-in 'c:\comserver\myserver.exe /automation'. Delete from list ? YES/NO
>
>
>Any specific guidelines, white papers or books to build this VFP server ?
>
>How to implement help to be displayed when, in Excel, I click on Insert - Function - Category MyServer.MyClass ?
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>
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>Thanks
>
>Juan