I have a situation where I need a VBA function to find some information from children tasks. The function works well when I call it from Immediate window in MS Project VBA in Global.MPT. The function is a public function and so i would expect to have access to it from the Formula in the custom field. However, I cannot see it in the lists of possible functions and I get a syntax error when I key it in manually. This is what I key in the formula: SummarryStatus([Unique ID]). I have other functions and subs in Global.mpt which execute when I open the project and when I press the Macro shortcut.

Here is the function although in this case it does not matter what the function is or what it does. I am asking how to call any function for a MS Project custom Field formula.

Public Function SummaryStatus(nT As Long) As String

Dim c As Task
Dim cT As Task, ipT As Task

    For Each c In ActiveProject.Tasks(nT).OutlineChildren
        If c.PercentComplete = 100 Then
            Set cT = c
        ElseIf c.PercentComplete <> 0 Then
            Set ipT = c
        End If
    Next c
    If Not cT Is Nothing Then
        SummaryStatus = cT.Name & " Completed"
    ElseIf Not ipT Is Nothing Then
        SummaryStatus = ipT.Name & " In Progress"
    Else
        SummaryStatus = "Not Started"
    End If
    
End Function