Gradient fill problem

I have been using CorelDraw since the day it came out. Just had to say that so the forum would know i do know my way around Coreldraw.

My PC systems rock!! all i7's, 32 ram, SSD, high end graphics cards.

Corelx8 STILL drags, slowest Corel yet. Had to get that off my chest.

Now to my problem.

I have a gradient fill (CMYK) top is 100% yellow to 100% yellow 100% black. If i click on the slider and add another point, it will show me what the gradient color is.

Lets say i click about 75% to the top of the slider bar, IT should be a fill of about 100% yellow and 25% black. IT does not!! it shows it as an RGB color, once i convert that color to CMYK.

it has a percentage of Cyan AND magenta as well as the yellow and Black.

IT should only contain percentages of Yellow and Black.

Can't someone explain what is going on, and how to (BY default ) use CMYK.

 We print T-shirts as well as car wrap vinyls.

Thanks,

Dave