If you get a custom property, it's necessary to attach "($cell_usr$)_" to a name.
Const prpName = "CELLA"
Set cmps = pcbDoc.Components(epcbSelectSelected, epcbCompGeneral, epcbCelltypePackage, "*")
For Each cmp In cmps
Set prop = cmp.FindProperty("($cell_usr$)_" & prpName)
If Not prop Is Nothing Then
MsgBox prop.Name & "=" & prop.Value
thank you very much, it was just what I needed.