Just some more comments. A have a ccf file now (with custom IR codes to communicate with HomeVision), generated from a script that was compiled with CCFCompiler.exe. The script itself was generated with a program that I have written in Visual Basic in Excel (vba). I will share this vba program later when it's a bit more user-friendly.
Although the codes can also be generated with ProntoUtil.exe, there is a discrepancy between the Device Code and Function Code put into ProntoUtil and the these codes recognized by HomeVision. After some detective work, it appears that the binary codes are reversed between ProntoUtil and HomeVision, with ProntoUtil using the least significant bit first, and the opposite for HomeVision. Although I don't know for sure which is correct, I suspect that most remote codes for Device and Function are beamed with the least significant bit first. If this is the case, HomeVision is actually incorrectly reversing the bits. Since the manual or any other information regarding HomeVision does not explain the format of HomeVision's "standard" IR format, it's difficult to judge.
-Rene