Do you have the XM10 interface. As you will need one of these, to control your X10 stuff.
The HV is very reliable. I use a Harmony 895 to control my HV. This remote came with the wireless IR sender. I stuck one of the remote IR eyes on to the front of the HV. I then used an old Sharp TV remote and taught the Harmony the IR codes and then labled the remote with lights on, lights off, Lounge bright lounge dim etc. Once I had done this I taught my HV these codes. Then assigned the relevant X10 commands to those codes.
You should also head on over to the HV forum/user group .
Programming the HV unit is quite straight forward.
I have set up certain timed operations. So that at a random time before sunset some of the lights in the lounge come on. I have a button set on my remote to bedtime. press this and the HV will gradually switch all lights off. The whole process takes about 15minutes, so plenty of time to get to bed etc. I did have a plug in module on my kettle so used to fill up the kettle plug it into the appliance module so when I woke up the kettle would have just boiled. I even have my pool pump controlled by my HV. It will detect when its summer an adjust the pump run times accordingly also I have a button on the screen to run the pump for 24 hours if I need it.
I suggest you have a look a Schelte's version of the HV software,as this will give you the control screen. Ideal if you have a touch screen on your PC. I even did a Star Trek inspired control screen for fun.
Need any more help just ask.