Using named range in user defined function

[Factotum]

I've run into a dead-end on this one, and I'm quite a novice when it comes to VBA. I've got a user defined function which is essentially a vlookup, but it returns cell comments also. I got this function from someone on this board a long time ago, but I'm sorry I don't know who to give the credit to. Anyway, the function is below:

Option Explicit

Function VlookupComment(LookupValue As Variant, LookupTable As Range, _
    ColumnNumber As Long, MatchType As Boolean) As Variant
    Application.Volatile True
    Dim res As Variant 'could be an error
    Dim myLookupCell As Range
    res = Application.Match(LookupValue, LookupTable.Columns(1), MatchType)
    If IsError(res) Then
        VlookupComment = "Not Found"
    Else
        Set myLookupCell = LookupTable.Columns(ColumnNumber).Cells(1)(res)
        VlookupComment = myLookupCell.Value
        With Application.Caller
            If .Comment Is Nothing Then
                 'do nothing
            Else
                .Comment.Delete
            End If
            If myLookupCell.Comment Is Nothing Then
                 'no comment, do nothing
            Else
                .AddComment Text:=myLookupCell.Comment.Text
            End If
        End With
    End If
End Function

I'm trying to use named ranges in this function as in:

 ActiveCell.FormulaR1C1 = "=VLOOKUPCOMMENT(NamedRange1,NamedRange2,2,FALSE)"

This method works great when using a regular vlookup function, but not with the user defined function. My end goal is to pull user input from one spreadsheet to a new, updated spreadsheet, I'm trying to make it somewhat user-proof so it can deal with a user adding or deleting columns.

I have considered using a loop along the lines of:

dim c as range

for each c in range ("NamedRange1")
      c.FormulaR1C1 = "=VlookupComment(first cell of NamedRange1 +1,first cell of NamedRange2+1,2,false) 
next

Each time through the loop would take the next cell in the named ranges, but I don't know how to make this happen. Any suggestions on how to make this UDF work with named ranges? Thanks in advance!!