Von der AS/400 aus leider nein.
Das Fach wird im Spool fix vorgegeben.

Prüfe mal beim Drucker (Handbuch, Doku), welche Einstellmöglichkeiten es so gibt.
Ggf. kann man auch eine andere Init-Sequenz (auch im WSCST) angeben, die das automatische Weiterdrucken ermöglicht.

Siehe hier:

Paper setup Def. paper size
A list of available paper sizes
appears.
Select the size for printing internal reports or
any print job that does not specify a size.

Def. paper type
A list of available paper types
appears.
Select the media type for printing internal
reports or any print job that does not specify
a type.

Tray n
NOTE:
n = 1, 2, or 3

Paper type
Paper size
Select the default size and type for the tray
from the list of available sizes and types.
Paper out action Wait forever
Override
Cancel
Select how the product should react when a
print job requires a size or type that is not
available or when a specified tray is empty.
Select
Wait forever to make the product wait
until you load the correct media and press

OK
. This is the default setting.
Select Override to print on a different size or
type after a specified delay.
Select Cancel to automatically cancel the
print job after a specified delay.
If you select either Override or Cancel, the
control panel prompts you to specify the
number of seconds to delay. Press the up
arrow to increase the time, up to
3600 seconds. Press the down arrow to
decrease the time.

Auszug aus dem Handbuch:
http://bizsupport2.austin.hp.com/bc/.../c01461642.pdf