That link gives a good breakdown of how to make pre-1.00 skins if that's what your looking for. 1.00 skins have a different syntax though. The 1.00 skins will start off:
[BSPlayer.Skin]
Version=1.00
The [Colors] area is for pre-1.00 skins. The [GUI] is for 1.00 skins. It is basically all the colors of the right-click menu and playlist.
MenuBackClr=788CD7 --
Color of Menu
MenuBackClrIco=4070B0 --
Color of menu around icons
MenuSelBackClr=80A4DF --
Color of selected menu item (highlighted item)
MenuFontClr=F8F8F8 --
Color of menu font
MenuSelFontClr=303030 --
Color of font of selected menu item
MenuDisFontClr=555555 --
Color of font of disabled item
MenuSeparatorClr=4070B0 --
Color of the separators in menu (i'd make them the same color as "MenuBackClrIco")
PlayListBackClr=6D82D3 --
Color of playlist
PlayListTextClr=303030 --
Color of file title in playlist
PlayListActTextClr=F8F8F8 --
Color of selected file title in playlist
I'll maintain my ignorance on the 'rgn.dat' file, but i do know that it is not necessary. The size of the skin would be the size of the image for the player minus any transparent pixels. 'MainAnySape' and 'ButtonAnyShape' just allow for transparent pixels (for curves) in a skin and/or buttons. 'MainAnySape' and 'ButtonAnyShape' can be 1 or 0 [1 for transparent, where pixel at (0,0) is the transparent color]. 'ButtonAnyShape' may also allow a value of 2, but i haven't tried this yet. I never noticed it but i guess 'MainAnySape' is mispelled.
[Volume] and [Trackbar]
PosSize=15,75,166,4
Kind=HB
or VB or H or V or Vbtn or Hbtn
Bitmap=seek.bmp
or ButtonImg=somefile (for Vbtn and Hbtn)
Border=0
BorderColor=303030
TransparentBg=1
or 0
BackColor=303030
'EXtrNum' is a pre-1.00 syntax which has been replaced with 'Number=
the number of buttons' under the [Button] area.
'StatTxt' is for the display of the time/button function/trackbar position on a skin in fullscreen mode. I use it only in my full screen ini file; not sure if it works in the main skin ini.