Hi Eric,

Can use Script SDK activity,

Public Class Script1
        Inherits RAScriptClass102
        '''<summary>
        '''This method is run when the activity is performed.
        '''</summary>
        Protected Overrides Sub Execute()
            'Write your code here. The BoundEntryInfo property will access the entry, RASession will get the Repository Access session
            Try
                Dim objFieldValueCollection As FieldValueCollection = BoundEntryInfo.GetFieldValues()
                Dim objFieldMultivalue() as Object = objFieldValueCollection("Field_Name")
                SetToken("Number_Multivalue",objFieldMultivalue.Length)

            Catch ex1 As Exception

            End Try

        End Sub
    End Class

regards,
Marco.