Open list form across host header site collections via Modal Dialog window

Question

Hello,  I have a web application that has two host header site collections in it.  When a user is on Host Header A, I need to open a list's display form that's located on Host Header B.  I'm using the JS function  SP.UI.ModalDialog.showModalDialog(options)
to open a dialog window to the host header B list's display form.  It loads and shows all the columns, but there are a couple issues.
1) The scroll bar on the dialog window is not active (can't scroll up or down to see all the columns).  This is an issue on all browsers (IE 8 &9, Chrome, FF)
2) In IE, the SP ribbon does not display.  In Chrome and FF the ribbon does display and the buttons work fine.
There's no errors in the ULS logs, and if I use IE8, there's a JavaScript "Access Denied" error.  I've confirmed the user account has permissions on both sites & list.
My first thought had to do with anonymous access being turned on at the web application level (not the site level) and the credentials not being passed to the new site collection.  But this isn't the case because in Chrome, the ribbon shows and the
buttons are security trimmed correctly based on the users permissions.  So I know the credentials are getting passed through the dialog window.  And when I use the "Edit' button on the ribbon in chrome, it opens a new dialog window and everything
works correctly (Scroll bar and ribbon).
Has anybody been able to successfully open a list form across two separate host header site collections?

Answer 1

I ended up getting around the cross site collection in the modal window issue by using a custom ASPX page that works as a redirect using JS.  
The link the end user clicks pops open the aspx page in a dialog window.  I then pull the URL of the list item I want to open from the URL and have JS open that form in the modal window.  The key seems to be to open the redirect aspx page under
the same site collection as the list item you want to view.
Here's the JS that's in the aspx page.
<script type="text/javascript">
// We name the current dialog windown
window.name = "newSiteWindow";
// wait until we know the the JS lib is loaded
ExecuteOrDelayUntilScriptLoaded(loadNewSite, "sp.js");
function loadNewSite() {
//grab the list item URL from the URL of the dialog window using a pre created function
newURL = GetUrlParmByName("listItem");
//append our dlg query to the end so everything displays correctly. If you do not use IsDlg=0, the ribbon does not display and the window will not scroll.
newURL = newURL + "&IsDlg=0";
//use the current window to open the list item we want to go to.
window.open(newURL, "newSiteWindow");
</script>