I am really having a hard time understanding the diffuglety (or issue) here. have we not all agreed that US spelling is different to UK/Canadian/Oz/NZ spelling and that arguing these differences gets us nowhere? what is the special issue with license (or any of these others)? I will refer you to W3, which is the ne plus ultra of US references, and which prefers license for all forms (although licence rates an or for the noun and only an also for the verb).

http://home.mn.rr.com/wwftd/