newbie---- DAC 4-20MA

Hi all
I am new to hardware issues and I can use any help you can give me...I
am working on a simple project with parallax basic stamp...I have to
control a vfd that accepts 4-20ma...


Basically I was thinking to use a DAC chip controlled by the basic
stamp....

the resolution at the moment is not a problem....8 bit will suffice I
believe

I googled and one option I got was the AD421 but the problem is that
it uses a mosfet that I cannot find anywhere the DN25D FET transistor
from Supertex1.

What solutions can you suggest to my problem? Are there any
alternatives both to the AD421 or the fet?