Vista CD Burning File System set to mastered

Note: If/When it's done, this might be an interesting topic to read, but until then, this is just a scratch pad for me to keep track of what I've tried, and probably completely uninteresting and confusing to anyone but me. I'll keep updating this as I go, but I'll probably just make a new post if/when I get it figured out.

Goal: get Vista's CD burning software to default to "Mastered" file system, rather than "Live File System". I've searched everywhere, and lots of people are asking how to do it, but nobody seems to have any answers.

What I've found:
1) There's a key in the registry that is called excludedFS under CD burning...it contains entries for each of the four UDF file types, all of which are just blank, and neither setting them to 1 nor 0 disables any of the options, nor does deleting any of the values (or even the key itself).

2) HKCR\Shell.CDBurn\Shell\Prepare\Command lists the command "rundll32.exe shell32.dll,PrepareDiscForBurnRunDll %L". Now we're getting somewhere...
-rundll32.exe shell32.dll,preparediscforburnrundll told me that it couldn't find that entry point, so capitalization counts.
-A Google search for PrepareDiscForBurnRunDll found 0 (zero...NONE) results. Dang. Of course, that'll change now that I'm publishing this. You heard it here first, people! :-P
-A little experimenting found I can replace %L with E: or E:\ and get the 'format disk' dialog to pop up for the given drive. Great. Maybe I can pass another parameter to specify HOW it should run (ie: mastered as default)? But I can't find it...passing anything other than a drive letter causes it to not even (visibly) start.
-Interesting though, I found I can get this to pop up for a drive containing a professional CD-ROM and "Mastered" file system is disabled. I wonder what that would do...surely I can't add files to a CD-ROM! Anyway, since it's just doing that based on the type of CD inserted, that doesn't necessarily mean I can dis/enable either option at will. Presumably the same thing would happen if I ran that command on a previously 'closed' mastered file system CD.
-Naturally, none of the switches -? -help /? /help /1 /0 /m -1 -0 -m -mastered /mastered 1 0 m mastered did ANYthing-as I said, it just didn't run at all. Running it like E:1 does let it run, but doesn't change anything-live is still selected, and version 2.01 (default). Probably means that it won't take other parameters, at least AFTER the drive letter. But maybe not.
-I don't know much about dlls, so I did a google search to see if I could find a tool that would extract acceptable arguments, or the number, or something. I'm not hopeful, and indeed, it looks like it's not possible - you need documentation or information from the writer. I'll search for shell32.dll information. We'll see...

3) There's a key at HKCU\software\microsoft\windows\currentversion\explorer\autoplayhandlers\userchosenexecutehandlers\handlecdburningonarrival that says "MSPromptEachTime"...I wonder if changing this key does anything. If it didn't prompt each time, would it take my 'last selection' (mastered?). (tried it) ...No such luck. I need to do a search for MsPromptEachTime to see if there's an alternate phrase that I could put in there.

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-Things I've yet to search through the registry for:
udf
cdburn -halfway through this search (haven't gotten past HKLM\Soft\ms\win\currver\explorer\autoplayhandlers\handlers\mscdburningonarrival)
mscdburningonarrival
MSPromptEachTime
"cd burning"

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-Fun tidbit: Found I can change HKLM\Software\Microsoft\Windows\CurrentVersion\explorer\AutoplayHandlers\MSCDBurningOnArrival ->Action to something like "Boogie" and that shows up in the autoplay dialog rather than "Burn files to CD" like @%SystemRoot%\system32\shell32.dll,-17416 pointed to