Below is how I worked around the above issue:
ReportViewer.prototype.OnReportLoadedOld = ReportViewer.OnReportLoaded;
ReportViewer.prototype.OnReportLoaded = function() {
this.OnReportLoadedOld();
var reportFrame = document.getElementById(this.reportFrameID);
var reportDocument = reportFrame.contentWindow.document;
var body = reportDocument.getElementsByTagName("body")[0];
$(".a1", body).css("text-decoration", "underline");
$(".a0", body).css("text-decoration", "underline");
You can achive the hover like this:
$(".a1", body).hover(function() {
$(".a1", body).css("text-decoration", "underline");
}, function () {
$(".a1", body).css("text-decoration", "underline");
});