How can I select a specific basemap w/o adding it to the MXD?

[San_Mateo_CountyGIS]

I'd like to have a different basemap for each of my webmaps but I don't know where to select the basemap I want.
If I change the basemap when the map is online already (arcgis.com) I have to save it under a different name and I can't see the new map in my REST directory.

Is there a way to select a basemap NOT in the MXD?

Thanks

[MikeMinami]

I'm not really clear on what you are trying to do...

• Are you trying to upload and store MXD files in 'My Content' of ArcGIS Online?


• Are you creating map services using ArcGIS Server and you're wondering how to organize the layers inside your map services (via the mxd) so that they can be mashed up into web maps easily?


• Something else?

Mike