This would be a question for Skins folder, not for Support.
To make bitmapfont you need:
1) Add a bitmapfont:
Add a line in the elements.xml file.
<bitmapfont id="bitmap.numbers.lt.grey" file="images/Numbers-Large-White.png" alphabet="0123456789:AP/-." separation="-12" opacity="65" />
<bitmapfont id="bitmap.numbers.white.small" file="images/Numbers-Small-White.png" alphabet="0=6;1=6;2=6;3=6;4=6;5=6;6=6;7=6;8=6;9=6;.=3;/=6;:=4;A=6;P=6;M=6;U+20=4" />
Here you have 2 different kinds of bitmap fonts.
The first one is the simple one. Only set the characters, the separation between two of them, and the opacity, amongst many others. Each character has a fixed width/height set by the width/height of the bitmap file. (See "skin format/skin format/bitmapfont" in the help for more info).
The second one is just like the other, except that every character has different size.
2) Set colors:
One easy way to make several colors to use is set hue="value" (from -1.0 to 1.0) in the bitmapfont.
Another way is set hue="%variable_name%" in the bitmapfont, using a red font.
Then, add this line in the skin.xml file:
<variable name="variable_name" default="0.0" values="Red:0.0;Orange:0.1;Yellow:0.2;Green:0.35;Cyan:0.5;Blue:0.65;Magenta:0.85;" description="Defines the color of the font." />
3) Create a bitmapfont:
You need any paint app which support transparencies (like Paint.NET, Gimp, etc) and add a text (try to make the same space between characters). Then change the alphabet value to the bitmapfont. E.g. alphabet="0123456789ABCDEFx" if you're trying to do an hexadecimal text.
Hope this helps you.