Though Sothink HTML Editor can not insert Flash movie into it, you could use the method below to have a try which is also easy to follow.
There are two situations.
1. If you create the flash movie by your own with Sothink SWF Quicker( you could also use other Flash Makers).
A.As the step of publish the flash movie, please select View or copy HTML code. You will get the code which could belong to this flash movie.
B.Then you could add this code of the flash movie to the body part of HTML in Sothink HTML Editor.
*Before preview if the flash movie is insert into the HTML page, please make sure that both Flash movie and the HTML are kept in the same folder.
2. If you want to insert the Flash movie which is created by other
Please add the following code to the body part of HTML in HTML Editor and replace the swf.file name( in red)with the one you what to insert in the HTMLpage.
<object classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=7,0,0,0" width="400" height="300" id="Untitled2.swf" align="middle">
<param name="allowScriptAccess" value="sameDomain">
<param name="movie" value="Untitled2.swf">
<param name="quality" value="high">
<param name="bgcolor" value="#ffffff">
<embed src="Untitled2.swf" quality="high" bgcolor="#ffffff" width="400" height="300" name="Untitled2.swf" align="middle" allowScriptAccess="sameDomain" type="application/x-shockwave-flash" pluginspage="http://www.macromedia.com/go/getflashplayer">
Then preview the page, you will get the flash movie on it. ]
Please have a try. Hope it is helpful.