Quicktime Custom Settings converting flipcam HD footage

Hello all,
I am using a script to convert some Flip cam MP4 files to 1080p DVC Pro HD files or Apple Pro Res 422. The problem is, as far as I can tell, there is no way to dictate the custom settings through Applescript. I had a look through the dictionary and found this:

export‚v : Export a movie or track to a file
export specifier : the movie or track to export
to file : the destination file
as AIFF/Apple TV/AVI/BMP/DV stream/Fast Start QTVR Movie/FLC/hinted movie/image sequence/interframe compressed VR object movie/iPhone/iPhone cellular/iTunes/MuLaw/MPEG2/MPEG4/picture/QuickTime media link/QuickTime movie/QuickTime TeXML/standard MIDI/System 7 sound/text file/ThreeGPP/wave : the desired file type
[using default settings/most recent settings] : the export settings to use
[using settings preset text] : the name of the export settings preset to use
[using settings file] : the file containing the export settings
[replacing boolean] : should the original file be deleted first?

The one I am interested is maybe “Using settings file” or “using settings preset text.”
How do you make/specify these custom settings?

Thank you so much for your help.

on run
	set thempegsfiles to the (choose file with prompt "Choose MPEGS to Convert to MPEG4 " multiple selections allowed "true")
	repeat with acoolist in thempegsfiles --used to loop through the list
		tell application "QuickTime Player 7"
			open (acoolist as alias)
			set mystring to acoolist as string --this sets the 'type' acoolist to a string 'type', i.e. coercion
			set newstring to mystring & "-new"
			if (can export document 1 as MPEG4) is true then
				with timeout of 50000 seconds
					tell (export document 1 to newstring as QuickTime movie using most recent settings)
					end tell
				end timeout
				display dialog "Can't Export as MPEG4 Movie"
			end if
			close the front window
		end tell
	end repeat
	tell application "QuickTime Player 7"
	end tell
end run

The problem is, I am not able to dictacte

You need to create a separate settings file first for each of the different export types. Then in your script you can use whichever settings file you wish. I posted how to do that in post #7 here:
Note that you’ll have to change “quicktime player” to “quicktime player 7” if you’re using 10.6.

Thank you! I will check this out!