NMAP2 Loops of Objective Analyses

Hey all,

I am creating some hourly, 3-D objective analysis grids in real time in
GRIB-2 format, and then I am passing these into GEMPAK for real-time
viewing on NAWIPS/NMAP2.  Because this is a rather large volume of data
each hour (the grid is 448x320x31 with numerous variables), it is
necessary to save each hours data into individual GEMPAK files.

This mostly works fine, except that within the NMAP2 application, I
cannot view more than 1 frame in a loop.  When I select the data set, I
can select any of the time for which I have files, but once I select
that time and a subsequent parameter to view, the time selector only
presents me with the data that is contained within the file I selected.
This is different behavior than image files and surface observation
files, where NMAP2 lets you "span" multiple GEMPAK files when selecting
the times to view.  Am I missing something in my configuration?  In my
datatype.tbl, I use this entry:

LAPS_US      $MODEL/laps               YYYYMMDDHH_laps_us.gem
CAT_GRD  SCAT_ANL    6   1440     -1      OFF/0/0      4

I thought the "SCAT_ANL" entry along with the time info would solve the
problem, but it doesn't.

I could partially get around this by dumping everything into a daily
file (it would probably be too big of a file though), but I think I
would still have the same problem right after the day changes (i.e., a
forecaster could not load a 00Z analysis from the latest daily file in
conjunction with some data from the previous days files as individual
frames in a loop).

I figure I could write some scripts that use gccfil/gdmod/gddelt to set
up a "circular" gempak file that always contains the last "n" hours of
grids, but that seems cumbersome if there is a way to configure NMAP to
span the grid files for times.  Any ideas?

Best regards,