It's now possible to add multiple kml-files to the map (version 2.12 and higher).

With the Google renderer, you'll need to set the center of the map yourself.

{mosmap kml[0]='http://tech.reumer.net/images/florida.kml'|
kml[1]='http://tech.reumer.net/images/allservices.kml'|
centerlat='0'|centerlon='0'|zoom='1'|
kml[2]='http://tech.reumer.net/images/Countries.kml'}

JavaScript must be enabled in order for you to use Google Maps.
However, it seems JavaScript is either disabled or not supported by your browser.
To view Google Maps, enable JavaScript by changing your browser options, and then try again.

With the GeoXML renderer, you don't need to set center. It will zoom automatically. Also you can sort the items inside a kml file in the sidebar (asc or desc)

{mosmap kml[0]='http://tech.reumer.net/images/florida.kml'|
kml[1]='http://tech.reumer.net/images/allservices.kml'|
centerlat='0'|centerlon='0'|zoom='1'|
kml[2]='http://tech.reumer.net/images/Countries.kml'|
kmlrenderer='geoxml'|kmlsidebar='left'|kmlsbwidth='200'|kmlsbsort='asc'}

JavaScript must be enabled in order for you to use Google Maps.
However, it seems JavaScript is either disabled or not supported by your browser.
To view Google Maps, enable JavaScript by changing your browser options, and then try again.

If you configured at the configuration to use [] or both {} and [] around mosmap then you need to use () for multiple kml. So:

[mosmap kml(0)='http://tech.reumer.net/images/florida.kml'|
kml(1)='http://tech.reumer.net/images/allservices.kml'|
centerlat='0'|centerlon='0'|zoom='1'|
kml(2)='http://tech.reumer.net/images/Countries.kml'|
kmlrenderer='geoxml'|kmlsidebar='left'|kmlsbwidth='200'|kmlsbsort='asc']