Alright this is how you do it....
Load up the control panel, add a custom vB code name it [swf] or [flash] and insert the following into the code field
create another custom code and name it [/swf] or [/flash] (corrisponding to the first one) put the following into the code field
Code:
" quality="high" pluginspage="http://www.macromedia.com/shockwave/download/index.cgi?P1_Prod_Version=ShockwaveFlash" type="application/x-shockwave-flash">
That should do it, to use it just type [flash]http://urltofile.swf[/flash]