soundcard calibartion question

I have a quick question about calibrating the soundcard in REW.

I am using a creative soundblaster mp3+ soundcard, connected to a behringer eurorack 802 mixer. Instead of connecting my in and out on my soundcard, would it be okay to loop the mixer in as well? That way I can correct for both the soundcard and the mixers responce, thus correcting for one more system component. Seems like a good idea, but is there any reason this wouldnt work correctly, software wise?

Thanks.

[JohnM]

Should work fine, best way to do it.