Portfolio galery B&W on hover

Hi,
some time ago you advised how to do a B&W picture in Portfolio galery. It looked super. The code was:

/*BLACK&WHITE colors portfolio grid*/
#top .grid-entry .inner-entry a { filter: grayscale(100%);
-webkit-filter: grayscale(0%);
-moz-filter: grayscale(0%);
-o-filter: grayscale(0%);
filter: gray;
-webkit-transition: all .6s ease;
transition: all .6s ease;
-moz-transition: all .6s ease;
-o-transition: all .6s ease; }

#top .grid-entry .inner-entry a:hover { filter: grayscale(0%);
-webkit-filter: grayscale(95%);
-moz-filter: grayscale95%);
-o-filter: grayscale(95%);
filter: none; }

#top .grid-entry .inner-entry a:hover {
opacity: 1; }

Now we found that it works perfect in Chrome and on iPad2. In Mozilla it works oposite (the pistures on the page are B&W and get colour on hover. Moreover, there is no effect at all in Interenet explorer.
You can check it out here: http://www.toptravel.com.pl/narty-alpy/
Would you please take a look and advise.

Kind regards
Tomasz