Alright, so I played around with WAIK (version 3.1, Windows-7-based) and HDSentinel appears to run just fine under it - amazing, you've managed not to depend on anything fancy, and not to crash when things (like the Systray, WMI, etc) are missing completely. Realtime performance data is unavailable, but SMART and disk tests work fine. Here's a quick guide; use Google to customize this further (like setting screen resolution to 1024x768 instead of default 800x600). Also, all your paths will be different than mine, obviously...
1- Get and install WAIK
2- Open the WAIK command Shell
3- CopyPE x86 D:\WinPE31
4- Copy D:\WinPE31\winpe.wim D:\WinPE31\ISO\sources\boot.wim
5- DISM /Mount-Wim /WimFile:D:\WinPE31\ISO\sources\boot.wim /index:1 /MountDir:D:\WinPE31\mount
6- To add drivers -> DISM /Image:D:\WinPE31\mount /Add-Driver /Driver:D:\MyDrivers /recurse /ForceUnsigned
7- Copy your registered HDS Portable to D:\WinPE31\mount\HDS
8- Modify D:\WinPE31\mount\Windows\System32\startnet.cmd and add "@PATH=%SYSTEMDRIVE%\HDS;%PATH%" (no quotes)
9- DISM /image:D:\WinPE31\mount /set-ScratchSpace:128
A- DISM /unmount-wim /Mountdir:D:\WinPE31\mount /commit
B- Oscdimg -n -bD:\WinPE31\Etfsboot.com D:\WinPE31\ISO D:\WinPE31\HDSBOOTABLE.iso
C- Burn the ISO...
Boot with the ISO and just type "HDSentinel" in the Shell, and voila :-)
If you want HDS to start automatically, just add HDSentinel.exe to the startnet.cmd...
If you want HDS to start maximized (and centered on screen), modify your HDSentinel.ini, add MAX=1 to the [Width] section...