Logitech Harmony 890 won't operate VTL 5.5 Preamp

I was given a Harmony 890 as a gift by my son to help alleviate the myriad of remotes I use. I have been able to get it to work with every component I have, with the exception of my VTL 5.5 preamp. I have tried downloading codes the normal way, and learning from the VTL provided heavy block metal remote. Any help getting the 3 commands(Volume up/down;mute;phase) working with my VTL 5.5 would be greatly appreciated. Normally, I'm pretty skilled getting electronic items working, but have to plead insanity on this one. Thanks in advance for any assistance.
Ask VTL what frequency their commands are on, then check to see whether the Harmony even operates in that range. For example, my "universal" Pronto cannot control a Pioneer cd player - the Pioneer commands are in a range outside the parameters of the Pronto. Made the dang thing kinda useless, to me.
I had the harmony learn the codes from the VTL remote on my 7.5. This did it.

I tried learning the codes from the 5.5 remote, but none of them seem to pick up. Do they use RF on the 7.5 now and something other on my VTL 5.5, Series 4, do you know by any chance? This has me frustrated, since I thought learning them would work too, but no luck. OR, I'm doing something wrong and think I'm doing it right.

Here's what I do to learn the codes. I place the two remotes face to face; put the 890 in learning mode; then push the volume button on the VTL to learn it, right? Thanks

Yes but you need to experiment with distance between the remotes. There might be something else I don't know going on, but the VTL always gave a problem to learn. I did it but after several tries. I first programmed my VTL w. the a Hometheater Master Remote. I ended up shipping both remotes to get it programmed. With the Harmony, I programmed it myself and it worked out OK, but took several tries and experimenting w. distance. Yes it is ridiculously time consuming. Maybe Harmony can offer a similar service to get the codes. If so I would love to know.