Terryballdmx
I want to wrap up the discussion for you a little bit.
You have currently two choices on the table:
1. Purchase a Hardware DMX Merger and a DMX Controller as boneshaker suggested and do everything in Hardware. The financial damage will be about 150 Euro for the Merger and Controller
2. Purchase a DMX Interface that can be connected to a computer with DMX-In and DMX-Out. You connect your Foot Controller to the DMX-IN and your lights to the DMX-OUT. That way you have full control on which DMX-Lines go where. In your case I would simply cut the 1st DMX-Channel and only forward the Channels 2-... and control channel 1 (the dimmer) with the software DMXControl. The Software ist free of charge, the cost for the Interface similar to the Option 1, but the advantage is, you can use DMXControl to do way more with your lights then you can do with your preprogrammed Foot controller. The disadvantage is, you need to have a laptop included in the setup, which I don't know if that is what you want.
Remark regarding the DMX Interface. There are Interfaces on the market that have an HTP Merge function Build in, so they can inside the Interface mix the DMX-Stream from the Computer with an external DMX-Stream like your foot controller. Personally I don't see the advantage of doing so if the Software supports reading DMX-IN Information (like DMXControl does). Maybe the reason some Interfaces support this is that some software doesn't support using DMX-IN.
So, now it's up to you to decide which way to go. If you choose Option 2 and have more questions, don't hesitate to ask them. You can also try out the freeware software (DMXControl 3.2.1) we are offering at http://www.dmxcontrol.org before taking a decision.
Regards,
Arne