forum hover over img problem

Hi all
can some one tell me how i can get around this little problem
right now on my test site i have a skin im working on and want it to look like this demo http://demo.phpbb3styles.net/Titan the bit im stuck on is i dont know the code to place in the CSS page to make it like this
I have the 2 images for the hover over but im stuck on the code can some one Please help me

My test site link is: http://achatworld.darkbb.com/
Theme version is: phpBB3 (prosilver)

If some one can also help me with how to put the dark bit for the Test Category 1 part aswell that would be really fab but if not then just the first one would help heeps

Much thanx
Ape

Use this css code and add the images.

Code:

li.row {
    background: url("IMAGE_HERE") repeat-x scroll #DDE7E9;
}

li.row:hover {
    background: url("IMAGE_HERE") repeat-x scroll #DDE7E9;
}

THANK YOU Matti_7