I am currently using NickieB's X2100 CVPI and it looks much better when the primary and secondary lights are activated at the same time. However, I have my mouse buttons mapped through SetPoint so that I can activate the primary lights with one of the side buttons, the siren with the other. However, I cannot configure SetPoint to utilize two normal keys at the same time on one button. Has anyone else been able to accomplish something like this?

Don't think it's possible. Unless you have a keyboard (or something) that has macro keys. For example Logitech gaming keyboards with "G keys" with can be mapped to a "macro" (more than one button in a certain order) so you could set it up like that.