How to do Vista/UAC aware self-extract installer

I distribute my software with a WinZip self-extract archive (SFX).
I am aware of this and that. But those doesn't seem to work for SFX scenarios.

While installing, the SFX unpacks and starts a contained program (written by me), that does the installation. This includes the creation of a registry entry for the programs list under the windows control panel. Further, the program has a manifest. So it should be "Vista-aware". The SFX-executable also includes a manifest.

The problem is that the Program Compatibility Assistant (PCA) throws its message "This program might not have installed correctly" anyway. So my customers tell me i'm a bad programmer...

I googled a lot, and read a lot about the PCA, including many Microsoft sites.
Those tell me to do:

1. embed a manifest
2. create registry entries for the programs list under the windows control panel

My manifest looks like this:

<?xml version="1.0" encoding="utf-8"?>
<asmv1:assembly manifestVersion="1.0" xmlns="urn:schemas-microsoft-com:asm.v1" xmlns:asmv1="urn:schemas-microsoft-com:asm.v1" xmlns:asmv2="urn:schemas-microsoft-com:asm.v2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <trustInfo xmlns="urn:schemas-microsoft-com:asm.v2">
    <security>
      <applicationRequestMinimum>
        <defaultAssemblyRequest permissionSetReference="Custom" />
        <PermissionSet class="System.Security.PermissionSet" version="1" Unrestricted="true" ID="Custom" SameSite="site" />
      </applicationRequestMinimum>
      <requestedPrivileges>
        <requestedExecutionLevel level="requireAdministrator" uiAccess="false" />
      </requestedPrivileges>
    </security>
  </trustInfo>
</asmv1:assembly>

So where did i go wrong?
Are there any further things to do for the PCA?
Do the SFX executable have to include some other things?

We fixed a similar issue in NSIS by setting a version field in the PE header to 6.0. I believe that was for our uninstaller but it might apply to your scenario as well.