Hello Juergen,
Yes, this is not documented. You can use this site for example to convert the three RGB values into a Hex value
http://www.colorschemer.com/online.htmlFor example RGB(255,204,51) will become a Hex value of # FFCC33.
Now you must convert the hexadecimal value FFCC33 into a decimal value.
For example here with this site
http://www.binaryhexconverter.com/hex-t ... -converterThe resulting color is 16763955
So enter the value "16763955 RGB Value" or just "16763955" into the Color field.
byee
Andrea