Selecting Printer

My PC has two printers connected, a HP Laserjet 4L and an OKI Microline 521
dot-matrix which is the default printer.

I have a workbook for which I have set up a custom paper size to print to
the dot-matrix. When I start Excel and print something it uses the custom
size defined, but when I print something from Excel choosing the HP laserjet
and then choose to print something  with the OKI it doesn't use the
user-defined paper-size but an A4 type of paper.

I thought a macro would be a solution to this, so I recorded a macro by
selecting File..., Page setup..., defining the custom paper size etc.
choosing the OKI printer and printing but when I tried it, it didn't work,
and when I had a look at the macro code it did not have any reference to
selecting the OKI printer and setting paper size etc.

Anybody have a clue as to how I can do this, or can it not be done at all.

TIA
Nikos