Promblem with jQuery ISOTOPE: Ignore one element or pinup with "sortBy : 'random'"

Promblem with jQuery ISOTOPE: Ignore one element or pinup with "sortBy :
'random'"

I have problems when using jQuery ISOTOPE: How can I ignore one block (or
put it stably in some place) when using "sortBy : 'random'". Here'.span12'
is my container. I have this block "div class="block-wrap has-logo"" which
I want to put it forever on the top-left of my page.
jQuery('.span12').isotope({
itemSelector : '.block-wrap:not(.has-logo)',
sortBy : 'random',
cellsByColumn: {
columnWidth: 222,
rowHeight: 222
}
})