SFX Self Extracting Installer With UAC?

[FarmerPete]

I've been using 7 Zip self extracting installers for a few years now, and everything has been working great. As I've started looking at the future (Windows 7), I realized I should probably start to make my packages UAC compliant. About 1/3rd of my self extracting installs are just msi's with the switches embedded into the SFX file, 1/3rd are bat files that issue commands, and 1/3rd execute VBScript files to do the heavy lifting. I've been looking around at how to tell Windows that it needs to give you a UAC prompt to elevate the credentials, but I've fallen a bit short. I can do it easily for a vbscript file using PrimalScript 2009 (It will package the vbscript file into an exe and add the manifest automagically for you). But, ideally I want to make it so that the SFX installer is the one prompting for UAC. Mainly I want to do this so that if UAC is needed, it will prompt, the user can accept/enter credentials, and then walk away while the install happens. Many of our installs are 600mb or so, and that can take a bit of time to extract. I tried using mt.exe to embed the elevation manifest into a SFX, but it turned a 550mb installer into a 49k installer. I've done a bit of looking, and it seems that I am not the only one to have that issue. Anyone have an idea on how I can create a SFX that will prompt to elevate credentials as soon as you click on it?

Most of my installs are done at the system build time, in which case the system is logged in as "Administrator" and wont get UAC prompts. However, some of my installs need to be run by non technicians who can't be bothered with "right clicking" on a file.