Use VRAA6S3. Even though it's not a direct correlation it will work just fine. The difference between the two is nothing more than the way the PCM detects glow plug faults. Obviously you will notice far different driving characteristics between what your factory PCM does and what the "wrong" calibration will do but it's normal. (Not speaking for what your current F5 tuning is doing.)
I think technically, PHP's library has a stash of VNAA8K8 calibrations but don't take it as gospel. These will be a direct replacement for your current hardware.
By using VRAA6S3, you will have access to the most refined calibrations on the HydraFlash server due to popularity of the calibration. Just be sure to order VRAA6S3 calibrations from the vendor of your choice should you decide to try tuning from a company other than PHP so you can maintain switch-on-the-fly capability if you decide to go this route.
I'll probably register the copy of HydraFlash I have had on my PC for a few years so I can give more direct answers about what's available.