Unless I have the wrong version, there is not disabled icon. Disabled computer accounts show up the same as the enabled accounts. Below is the bit of code that mentions the icons.

Code:
  
If Exist("%WINDIR%\System32\dsuiext.dll")
	$c=$imgList.Images.Add("dsuiext.dll;1")
	$g=$imgList.Images.Add("dsuiext.dll;7")
	$u=$imgList.Images.Add("dsuiext.dll;12")
	$o=$imgList.Images.Add("dsuiext.dll;13")
	$ux=$imgList.Images.Add("dsuiext.dll;27")
	$ul=$imgList.Images.Add(".\user_locked_16.ico")
	$f=$imgList.Images.Add("dsquery.dll;0")
	$frmMain.Icon = $imgList.Images($f)