loading automation add-in for an instance of Excel

[Smallweed]

I know that when you start an instance of Excel with VBA code, the add-ins
don't load which means you have to open or install them individually in the
code. For an XLA that's fine but I'm using an automation add-in (in version
2002). I've tried the following line:

AddIns("MyAddin.ForExample").Installed = True

but this doesn't do the trick. Does anyone know a way or will I have to go
the old-fashioned route and develop a VBA wrapper formy DLL?

 

[Smallweed]

An update:

I've found that uninstalling first helps:

AddIns("MyAddin.ForExample").Installed = False
AddIns("MyAddin.ForExample").Installed = True

This kick-starts it but I then find my UDFs don't recalculate, whether I use
Calculate, ActiveSheet.Calculate or Range(...).Calculate.

I can get a UDF to update if it's in a VBA wrapper:

Function vbaUDF(a, b, c)
vbaUDF = Application.Run("MyAddin.ForExample.dllUDF", a, b, c)
End Function

as I guess this has the effect of recalculating BUT I DON'T WANT TO DO THAT!

Any ideas out there??