Hi Steakers
The 4 terminals you have on the back of the speakers are there if you want to bi-wire the speakers, if this is something you wish to try you would need to remove the Jumpers from the terminals, you would also need to buy bi-wire speaker cable. Assuming you watch films more than music you need to think about weather the improvement would warrant the upgrade and outlay, if music is your priority then there may be an improvement bi-wiring. Looking at your set up it looks like you are film fan, some forum members and others have said that they have heard an improvement when bi-wiring, others have not, if you want to try the best way is to buy some cheap speaker cable and give it a go, its not the best way to do it as buying cheap speaker cable might not give you the improvent you want over a proper bi-wired and more expensive cable, unless you know a dealer that has bi-wire cable they could let you borrow to dem, at the end of the day if you are happy with the sound then stick with normal termination, if you really want to go the upgrade path then purchase new speaker cables, this give you an improvement over what you have [assuming they are not already quality cables] there are plenty of reviews on this site, QED and CHORD are cables you wont go wrong with, below is a good suplier very freindly and relaible, call them if you need any advice.
Hope this helps
http://www.hificables.co.uk/