This functionality is not supported in Recommendations as of now.
I have gone through the documentation, to no avail. Perhaps I did not explain this well enough...
[I tried to put the image in this reply, but it only let me attach - please see attached image]
The numbers you see in the image, change dynamically when you click to scroll through a carousel.
I have not tried this yet, but does Recommendations allow the use of regex in a template?
And I need to allow both positive and negative prefix notations like so: /^([+-](?=\.?\d))?(\d+)?(\.\d+)?$/
You may want to refer to the documentation present on http://microsite.omniture.com/t2/help/en_US/rec/t_create_edit_recs.html and see if the content helps. In case you have any other specific query do let us know.