How Do I Stop Conversion to Square Bracket Coding?

Now that I finally have Wysiwyg API up-and-running with TinyMCE, I tried a simple test. I opened a page node, copied the marked-up text from a web page including anchors, bolds, italics, etc. and pasted it into the rich text editor of TinyMCE. When I save the page, it converts stuff to square bracket notation, e.g. [url=...] instead of <a href=...>, [b] instead of <b>, etc. This has the undesirable side-effect of making the square bracket notation show up on the live page. So instead of a bold word I get a [b]bold[/b] word. How do I get TinyURL to stop converting to square bracket notation?