Our editor does not perform any filtering on the content (server or client side). All content stripping is done by SharePoint itself. You can verify this by trying the same content in a list item with our editor and then the default list editor.
By the way, the web part should allow flash objects. We have verified this with some sample object and embed tags. Perhaps there is a problem with the specific content that you are trying to insert? If possible, give us the HTML code so we can test it locally.