Problem with mic when using external sound card

I use Cross DJ 2.5 , U-Mix Control Pro and Native Instruments Audio 8 DJ sound card.
If I Plug a mic into the sound card I then have to allocate one of the channels to 'Line'. This can only be done on channel A Or B, so I would have to Use C and D for mixing . This is not very practical.
Even worse I cannot allocate the same output channel in audio preferences as the master out . But I only used two outputs from sound card . Master to amp and Cue to headphones ,so allocating to a 3rd channel is no good to me. So what I really want is a 5th mixing channel which I can allocate to the same output channel as master out (as well) which is not linked to the Cross fader. This can be done in Traktor Scratch Pro which I have . But in my opinion Cross DJ is far superior in every way. Please try and correct this oversight . Thanks Jim
If I Plug a mic into the sound card I then have to allocate one of the channels to 'Line'. This can only be done on channel A Or B, so I would have to Use C and D for mixing . This is not very practical.
Even worse I cannot allocate the same output channel in audio preferences as the master out . But I only used two outputs from sound card . Master to amp and Cue to headphones ,so allocating to a 3rd channel is no good to me. So what I really want is a 5th mixing channel which I can allocate to the same output channel as master out (as well) which is not linked to the Cross fader. This can be done in Traktor Scratch Pro which I have . But in my opinion Cross DJ is far superior in every way. Please try and correct this oversight . Thanks Jim