[gembud] SST data

Happy 4th!!!!!!!

I don't very often admit full defeat, but this time I am..
I started to use the gem file for the Atlantic SST's from the NCEP
ftp://ftpprd.ncep.noaa.gov/pub/data/nccf/com/nawips/prod

Took me a few stabs to get the grid values..
TMPK .. how on earth does one kick GEMPAK to convert this to F ??
I have attempted  (using GDPLOT3)
GDPFUN = SSTF, GDPFUN = TEMPF
these give me the dreaded "cannot be found" error's
so I tried the conversion formula and that gave me a blank map...

ok guru's be gentle..
what's the secret??

-Jeff