Wysiwyg Tiny MCE, problem adding custom links

Question

I am trying to see witch one i like best, Tiny MCE or CKEditor. The problem that i am getting is that i need to add a custom toolbar button (or extend the anchor button). Trying now to modify the advlink plugin to insert internal links from the CMS. So i modified the page link.htm and added one button next to the href field. This button opens up a small popup where the user can select an internal link in the CMS and then press insert. The small popup then uses javascript to send the result back to the link.htm page. The link is then inserted into the href field. My problem is that when i press insert on the link.htm page, it just reloads the page and nothing is inserted.

This is the javascript that i added to the link.htm page:

    function ShowInternalLinks() {
        window.open('InternalLink.aspx', 'InternalLink', 'toolbar=0,status=0,menubar=0,location=0,directories=0,resizable=0,scrollbar=0,width=400,height=200');
    }
    function InsertInternalLink(link) {
        document.getElementById('href').value = '/1/?' + link;            
    }

Nothing fancy, just opens up my custom aspx page when the ShowInternalLink is clicked. Then when the user clicks on insert on that page, the page calls the javascript InsertInternalLink and then closes the small popup. Everything works when i run the page, the href gets the correct value from the popup page, but when i then press insert, the page just reloads and the href field resets itself.

Any ideas? (If i write in the URL in the href field, it works perfectly. Just doesn't work when i use my popup window)

Side question: Can this even be done easily in CKEditor?