viewroot.findComponent - access field in row in datatable or datalist

[JP Bar]

Hi!, I've a form with a datatable with htmlinputtext and I want highlight particular fields in some rows. But I have to change the style without javascript, in the server.
For the rest of the form, I've no problem using viewroot.findComponent(":form:subview:idField") but with datalist or datatables I can't access to the rows with findComponent(":form:subview:idTable:numberOfRow:idField") always return null. I've been reading and I think rows aren't generated in server time?? or similar??? Perhaps I've to use another methods like invokeoncomponent or it's more simple?

Thanks in advance!