Native Instrument output to CEP record input

Please help.
I have CEP2.1, on a Dell Laptop, with a Tascam US428 controller
I want to record the output of my Native Instrument audio output (B4) to a trark in CEP. Both running on the same Laptop.
How do I internally route the audio output of the B4 synth to the record input on CEP.
I am not getting the signal into CEP. If I connect the audio output of the US428 to the input on the US428 I am getting the backing track audio recorded on the track as well.

Thanks in advance.
Dave

Ah, you just found one of the drawbacks of CEP not supporting VSTi's directly. The only way I managed this (and forgive me if I get something wrong as I haven't used CEP for some years), was to record the instrument panned hard left (on a mono track), while listening to the backing panned hard right. That way you don't record the backing again. It isn't pretty, but it may help.