getting serial.sys to work for an ISA based 4xserial port card to work

I have an ISA based card with 4 serial standard serial ports(16550
type) that share an IRQ (using a cpld) that I would like to use with
windows 2K.

As far as I can understand it, i can use the driver included with
windows (serial.sys) and I need to write a wrapper of some kind and an
INF file. Is this a correct assumption ?

Are there any links to information that more or less outline the steps
to do something like this ? (as i have no prior experience with
developing kernel mode drivers on microsoft platforms.)
I would just like to estimate the difficulty of this job first, it
seems to me that it should be fairly simple.

Thanks very much,