Sorry to keep you guys waiting - I'm working at a client site.
Not all RapidLED dimmable LED kits are compatible with the Apex. RapidLED is one of the few online vendors that offers multiple types of dimming control options with (some of) their kits.
There are 2 types of commonly-used dimmable drivers... one type uses a technology called PWM (Pulse Width Modulation), the other uses 0-10vdc analog control. The Apex does *not* work with PWM drivers.
Some of RapidLED's kit only come with a PWM driver. Other RapidLED kits do have the option to be ordered with your choice of PWM or 0-10v; these will be the ones that list the Meanwell ELN-60-48P or -48D driver options; for compatibility with the Apex, the driver model must the "D" suffix.
Other kits, which use the Meanwell HLG-series, are user-configurable as either PWM or 0-10V.
So, in a nutshell, just be careful what you order - if you are at all unsure, email them and clearly state that you want to interface the kit with an Apex.