How to add link (via php) to xmlsitemap I have a site where some pages are "virtual".

The path is : 

internal_node/XYZ 

where 
* internal_node/% is defined in a hook_menu()
* XYZ is a number

my "internal_node" callback  call an external service using XYZ like argument, get soma data and display this data to the user. All works without problem. And all is legal. 

Now I want to add all "interal_node" links to my google's sitemap.

I have installed xmlsitemap, but this module create a google sitemap for only all internal drupal node and my "internal_node" are not a drupal node. 

So, how can I add link to xmlsitemap ? 

Thanks.
you could put those links in a menu and have that menu included to your xmlsitemap.