Sorry for the delay, been real busy.
Just went to look at the site but it looks like you've been tinkering, I get the error:
$("#mygallery3085 a.next").live is not a function
http://www.wijzijnblits.nl/category/sterkemerken/
Line 110
(hint, try jQuery("#mygallery************* )
Looks like you're along the right lines, you'll either need to use the live hook (so new posts that are loaded will be binded to). Or you can use the "javascript callback" option in infinite-scroll to execute code that will enable the slideshow on all the newly loaded posts.
I'd probably continue trying to use jQuery's live function, cleanest way to do it. Let me know how it goes or if you need any assistance.
p.s. Awesome looking site!