Hi dsr,
Without knowing exactly what you are doing in your HII here's some pointers. Sorry if its stuff you already know!
.cfg files -> If you have have check the option for Altiris to reconfigure the machine after deploying your image it creates this to
sysprep.inf -> I would change this to sysprep.xml -in Windows 7, as they aren't actually inf files so its best to avoid confusion that suffix to avoid confusion.
Standard practice is to use %ID%.xml rather than %COMPNAME%.xml -this ensures uniqueness avoids the possibility of spaces getting in the way when you copy these little files around.
The computer name can only be configured to my knowledge in the XML during the specialize pass (see my blog). If doing this manually with a FIRM copy (rather than having Altiris copy it by referencing the sysprep file in the GUI) then you'll need to use a ReplaceTokens on the XML before copying over to the client.
When monitoring some of the files in the temp folder, Deployment server will do some cleaning up, so sometimes they are shortlived.
Hope at least some of that helps.