scusami avevo capito male, ke ne dici di una cosa di questo tipo?

codice:
Private Sub Form_Load()
Dim PRIMODELMESE As Date
Dim ULTIMODELMESE As Date

PRIMODELMESE = firstDayOfMonth(Now)
ULTIMODELMESE = LastDayOfMonth(Now)

db.Execute "SELECT * FROM TABELLA where Scadenza_pagamento between #" & PRIMODELMESE & "# and #" & ULTIMODELMESE & "#)"
End Sub

Public Function LastDayOfMonth(d As Date) As Date
    LastDayOfMonth = DateSerial(Year(d), Month(d) + 1, 1) - 1
End Function

Public Function firstDayOfMonth(d As Date) As Date
    firstDayOfMonth = DateSerial(Year(d), Month(d), 1)
End Function