Attempting to move C:\WINDOWS\Installer - wierd results

I'm playing with an eeePC 4G into which I've placed an 8GB SDHC card. The SSD C: drive is 4GB, the SDHC D: drive is 8GB. I'm working to move files off the C: drive to the D: drive to increase empty space on C:.

My strategy employs moving folders and creating symbolic links in their place. I'm using sysinternals junction to create the symbolic links.

I moved the contents of the folders C:\MSOCache and C:\Windows\Installer (more than 1 GB total) to D:\MSOCache and D:\Windows\Installer. Deleting the empty folders, I replaced C:\MSOCache and C:\Windows\Installer with symbolic links, i.e., "junction C:\MSOCache D:\MSOCache" and "junction C:\WINDOWS\Installer D:\WINDOWS\Installer".

Office mods appear to function as intended. That is, Office uses the D:\MSOCache without complaint. So far.

D:\WINDOWS\Installer is a different story. The msiexec installer in XP SP3 does not appear to like the symbolic link. During an msiexec install the symbolic link to D:\WINDOWS\Installer was removed, replaced with the folder C:\WINDOWS\Installer, then populated with an installation database .msi file.

On top of that, the D:\WINDOWS\Installer folder containing about 600 MB of installer files was deleted in its entirety(!) and replaced by a folder of the same name containing the same installation database .msi file as on the C: drive!

What screwy logic did that?

Maybe this has to do with a Group Policy against folder redirection. Maybe it's hardwired in the Microsoft Installer accompanying XP SP3. I don't yet know.

I'll report what I find. Any comments?

Harry