Thank you Agraham but I used the existing private method in the library, and the bitmap creation is reduced to this piece of code :
Code:
this.palette = new Bitmap(120,120) ;// create the palette bitmap
for (int h = 0;h <120;h++)
for(int s = 0;s <120;s++)
this.palette.SetPixel(h,s,HSLToRGB(h*2,240-s*2,120));
The library is updated to ver 1.1