Scale Broken In IE7 When Using Origin Argument

I've been trying to show a div using jQuery's show function with the scale effect. My code works fine in Firefox. When I test it in IE7, it breaks. I narrowed it down to either the origin argument of the scale effect, or the time argument of the show function (which seems unlikely). Like this:

Works in IE7, italics added to show commented code better:

Code:
$(document).ready(function() {
$("#hover").hover(
function() {$("#content_show").show("scale",{percent: 100, direction: 'vertical'});},//, origin: ['center','center']},500);},

[Code]....

Also, not as important, but what is the syntax of the origin property? What values can I use in it?