Recording in rekordbox using a allen and heath db4 mixer and cdj2000nsx2's ?

I have an Allen and Heath DB4 mixer and CDJ2000nsx2's connected to rekordbox.

I can play out of rekordbox no problems at all, but i cannot record to it.

I have the CDJ'S connected to each other and the cdj's are connected to my Mac via usb. The mixer is also connect to the computer via USB.but I use RCA's to connect CDJ's and mixer together.

I cannot select inputs channels in rekordbox. I hear alot of talk about ASIO drivers, but cannot find any to download specially for a A&H DB4 mixer.

 Help me please I am desperate to record and don't want to go back to serato which worked just fine before I moved to rekordbox.