I understand that you want to know if it is possible to add channels manually on the Electronic Program Guide (EPG).
Unfortunately, it is not possible. There's no way to add channels manually or apply any workaround. This option is not available yet and we do not know if it will be available any time soon. The listed channels are related to the Zip Code you use when running the Setup Assistant for Internet Viewing and TV source configuration. Besides, keep in mind that the EPG is supported only if the Slingbox is located in US or Canada.