gEDA-user: pcbexpress.com and ``pcb'' ``negative'' solder mask layers

["Joel N. Weber II" <jwgeda@xxxxxxxxxxxxx>]

A google search of the archives of this list seems to suggest that
someone who's posted here in the past has successfully made 4 layer
boards using ``pcb'' and pcbexpress.com; I assume this probably
included soldermask layers.

I tried ordering a two layer (that is, two layers of copper, two
layers of soldermask, one layer of silkscreen, plus the drill file)
board from pcbexpress today, and got back:

| Your Order [order number] IS HOLDING...  Both the top and bottom
| soldermask layers are negatives.  We require positive layers for
| all.
| 
| Please reply to this email and attach new or revised files; your
| order will be processed ASAP.

Do people have recommendations about how to deal with this?

(I don't have any particular strong reason to prefer pcbexpress, other
than that a friend who uses protel has been very happy with
pcbexpress, and their proximity to screamingcircuits looks convenient;
though I have no particular reason to prefer screamingcircuits,
either, if there's another viable board assembly company with
competitive service and pricing.)

Also, it seems slightly inconvenient that pcb is designed to generate
separate drill files for plated and unplated.