Memory Cache handler

I would like to use the memory cache manager but don't understand what I must implement.

The example in linemode browser use an HText_select function but i don't see what it really does.
And what to do if some of the request are inline images ?
For what i have seen, it seems that when you return HT_LOADED from the cache handler nothing more is
done... so how to associate your real object to the result of your request ?

Thanks in advance.