nice good work, I have been trying to place flash in there as well. I found code on another site, I think it was Joomlaboard.
[code:1]
//swf
$sb_message_txt = preg_replace("/\[swf\](.*?)\[\/swf\]/si","<object classid=\"clsid:d27cdb6e-ae6d-11cf-96b8-444553540000\" codebase=\"http:\/\/fpdownload.macromedia.com\/pub\/shockwave\/cabs\/flash\/swflash.cab#version=6,0,0,0\" width=\"400\" height=\"300\" align=\"middle\"><param name=\"movie\" value=\"$1\"
><embed src=\"$1\" quality=\"high\" bgcolor=\"#ffffff\" width=\"400\" height=\"300\" align=\"
middle\" allowScriptAccess=\"sameDomain\" type=\"application/x-shockwave-flash\" pluginspage=\"http:
\/\/www.macromedia.com\/go\/getflashplayer\" \/><\/object>",$sb_message_txt);
[/code:1]
Not sure if this works though. I am still yet to try it.
Found here.