Custom functions in mac excel 2008

[sschouela]

I use to be able to access custom functions that I wrote and imbedded in the local module of my spread sheet. These functions were written in VBA.

Is there any way now to simulate this with apple scripts.

For example:
My function call in the Excel spread sheet side was NAV(range) and in the local module was>>

Function NAV(myRange)
    NAV = 1
    For Each i In myRange
        NAV = (i + 1) * NAV
    Next i
    NAV = NAV - 1
End Function

I am hoping for a help because otherwise this will be then end of excel for me.