Does INSTALL.EXE for .NET 2.0 do something that our MSI does not?

In theory, distributing .NET Framework during ZEN Imaging is via an Administrative install MSI, adding the MSI property ADDEPLOY=1 for .NET 2.0+

DotNET 11 Install (v1.1.4322)
DotNET 20 Install (v2.1.21022)
DotNET 30 Install (v3.1.21022)

The AutoCAD 2008 Windows Installer (ACAD.MSI) requires only .NET 2.0 and seems picky about it, but we've not had any prior problems.

#1) ACAD.MSI errored(*) during ZEN Imaging with our standard .NET 2.0 distribution, but afterwards, when a user logged-in, ACAD.MSI added itself OK. We also saw this problem with DotNET 30 adding itself after imaging, which we aborted.

#2) I down-graded to a past Admin install of .NET v2.0.50727, the version supplied with AutoCAD, but ACAD.MSI again errored(*)

#3) ACAD.MSI installed OK if .NET 2.0 was installed via its INSTALL.EXE, so I tried a ZEN distribution of the local NETFX.MSI extracted from AutoCAD's support-files, but ACAD.MSI again errored(*)

#4) I saw that INSTALL.EXE for .NET 2.0 appears to call some executables, so I chanced WIC_x86_enu.exe + XPSEPSC-x86-en-US.exe as part of .NET 3.0. Running these after any MSI of .NET 2.0, and then ACAD.MSI installed OK

#5) I added WIC_x86_enu.exe and XPSEPSC-x86-en-US.exe with parameters of "/Q" as Application Dependencies of ACAD.MSI, but again ACAD.MSI errored(*)

Our Application Object for AutoCAD includes Microsoft MSXML 6 (MSXML6.MSI v6.10.1200.0) as an Application Dependency, and is Workstation associated. I tried both "Distribute in Workstation Security Space" and "Force run as user" options.

Any ideas? Thanks.

* ERROR: Product: AutoCAD 2008 - English -- Internal Error 2337 on "Autodesk.AutoCAD.Interop.Common.DLL"