StarTools

I used the synthetic luminance technique and then really increased saturation. It still doesn't look "red" enough and the RGB image has a really strong reflection nebula around NGC6559 that is getting lost as well (although it disappears completely when using just ha)

http://www.astrobin.com/194889/

Ok I have made a set of comparison images from my recent NGC6559 data.

NBRGBCombination - Ok stars and nice red color. Dark nebulas are hard to spot.
http://www.astrobin.com/194889/B/

SHO-AIP method suggested in this thread - Better contrast on dark nebula. Still nice red color. Crazy looking stars.
http://www.astrobin.com/194889/C/

StarTools- Synthetic Luminescence + LRGB Combine - Awesome stars and dark nebula detail. Awful pink color and the reflection nebula completely gone.
http://www.astrobin.com/full/194889/0/

StarTools - Synthetic Luminescence + Color Transfer Method - Nice stars and dark nebula detail. Color not quite as pink. Reflection nebula still missing. Edit: Looking at it now it just maybe the reflection nebula is better blended?
http://www.astrobin.com/194889/D/

Any idea why the reflection nebula is getting eliminated?

Since I'm at it one more attempt. This time using NBRGB combo but using the synthetic luminance for ha.

http://www.astrobin.com/194889/E/

D definitely would have my preference for the coloring.
While the pink may be awful to some, it is very much consistent with the composition and processes going on in a HII region like this - if the visual spectrum is of interest of course! I can still make out blue reflection-only nebulosity.
HII areas are pink due to dominant Ha emissions and light reflected from young O and B type stars that are born in these areas (these stars are the main drivers for the Ha excitation). Combine red Ha emissions and blue reflected light and you end up with something close to pink/purple.

Thanks after reviewing some other nebula images, namely by StarKeeper.IT I completely agree on the pink color and that D is the best. I would love to know why I loose some of the wispiness on the NGC6559 reflection nebula.

It's a tricky one, especially when relying on narrowband data (which in this case precludes the blue) as well.

depending on what you're looking for, you could use the Filter module to attempt to filter (reject) the red, while boosting (nudging) the blue;