Change map base maps

The map module is an awesome plugin for gallery. It has the 3 default base maps, but others exist, notably the terrain G_PHYSICAL_TYPE base map is essential in my opinion. Anybody add this base maps to their mod? I can't figure out which files I need to experiment on to get started.

Thanks

Gallery version = 2.2.2 core 1.2.0.4
PHP version = 5.1.6 apache2handler
Webserver = Apache/2.2.3 (CentOS)
Database = mysqli 5.0.45, lock.system=flock
Toolkits = ArchiveUpload, ImageMagick, LinkItemToolkit
Acceleration = none/432000, none/900
Default theme = carbon
gettext = enabled
Locale = en_US
Browser = Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.4; en-US; rv:1.9.0.5) Gecko/2008120121 Firefox/3.0.5
Rows in GalleryAccessMap table = 180
Rows in GalleryAccessSubscriberMap table = 8094
Rows in GalleryUser table = 5
Rows in GalleryItem table = 8092
Rows in GalleryAlbumItem table = 244
Rows in GalleryCacheMap table = 0