windows 7 professional, Digi ClassicBoard PCI 4-port, renumber COM port assignments

I have a Digi 4-port ClassicBoard with the DB25 cable installed
in the PCI slot of a Dell Inspiron 580 running Windows 7 Professional.

- Digi ClassicBoard PCI (5V) 4-port RS-232, Part #77000576
  PN (IP) 50001136-02 Rev B
  SN (S) V 11159830
- Digi 4-port DB25M, Part #76000008

I would like to renumber the COM ports from COM 4-7 to COM1-4 because
when using the Windows Virtual PC with XP Mode this virtual machine
set up does not recognize ports numbered greater than 4, consequently,
only COM4 can be mapped to the two COM ports supported by XP Mode.

Sometimes the Device Manager can show the Port Settings, Advanced button that
allows port numbers to be reassigned, however, this is not shown
for the Digi ClassicBoard PCI Port (COM4) properties.

Is there a driver update that allows the COM ports to be reassigned?