Walker605 wrote on Feb 8^th, 2018 at 1:32am:

Gnacino wrote on Mar 28th, 2011 at 7:35pm: Is anyone using this panel, or know if it works with the CS MCP? I gave up trying to make my MCPPRO work with it but I do use it with other ac. It sucks not being able to use it. If Saitek's work, then I get that. Any input will be appreciated. Thanks, Gnacino Gnacino, I have the saitek suite of panels and right now, they do not appear to be working. I just downloaded the newest update released this week, but have not had a chance to fly. I will test to see if the macro's/LVARS are updated so I can use the panels I have. If they are, I will report back here.

So your problem is with the 757 Captain III, and not the 757 Captain v4.6 for FSX (the update to 4.6 was quite a few years ago now). ;)
I think you should post your problem in the 757 Captain III - General forum