You can manually create a manifest file with a text editor. It would contain:
="1.0"="UTF-8"="yes"
<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
<trustInfo xmlns="urn:schemas-microsoft-com:asm.v3">
<security>
<requestedPrivileges>
<requestedExecutionLevel
level="RequireAdministrator"
uiAccess="false"/>
</requestedPrivileges>
</security>
</trustInfo>
</assembly>
If you save it in the same directory as your application, you should get the desired result.
The manifest file you save must be named with your application name and .manifest. For instance, if your application is called "MyApp.exe" then the manifest file would be MyApp.exe.manifest.
Another option is to simply name your application with a name containing one of the "triggers" for UAC. Admin UAC is automatically triggered if the app name includes "setup", "install" or several other similar words.
Hope that helps.