Hi!
Currently, it's impossible to define a custom path for ASPxHtmlEditorForms and ASPxSpellCheckerForms user controls, but you are free to add a new suggestion to our Support Center.
Thanks,
Andrew R
R&D, ASP.Net Team
Developer Express Inc.
PS. If you wish to receive direct assistance from our Support Team, use Support Center at http://www.devexpress.com/Support/Center