Please see the "options for commands" section of this manual for general information about the use of macros for configuration.
If you are creating a pure per-user install in Vista+ then you can force the install to run without elevated privledges and without the UAC popup dialog.
The default is that "Y" (UAC is presented), if this is not required then the "SourceType" summary property (PID_WORDCOUNT) has 8 (bit 3) added. This is done in "company.mmh".
Apparently if you have successfully prevented the display of the UAC dialog you should see this in a verbose log:
MSI_LUA: Package is marked as LUA installation capable with no elevation