[Solved] Flash and CSS

Hope someone out there can help me with this....

I dont use CSS that much really...so I only know a very little. My web page is fine and fully functional except for one thing - my banner. Originally I had a standard jpg banner ...and the code is as follows

#header {
margin:2em 2em 0 2em;
padding:1em 1.5em;
height:5em;
background-image:url('bluehd1.jpg');
background-repeat: no-repeat;
background-color:#000000;
border:1px solid #eeeeee;
}

"bluehd1.jpg" being the original banner.

Now I have made a flash banner, and I want to replace the jpg banner with the flash one. Now if I were just using straight html...I would use this code:

I even tested it out in a blank page..and the code works. My question is...how can I substitute the flash banner, for the jpg one.

As I said..I dunno much about css...and you might find the things I tried stupid...but oh well...after backing up all the files, I tried the following things myself:

1. leaving the style code exactly the same..just changing bluehd1.jpg to bluehd1.swf - didnt work

2. I then erased all the style code except for

#header {

and added the flash code...in various forms....then ended with

}

3. Last but not least I installed microsoft frontpage and using the "design" view - deleted the jpg banner and inserted the flash banner. This worked....only the banner wasnt the right size...it was like 75% smaller...and surrounded by a white box.....i then tried adjusting the sizes in the style code (2 em 0 em etc) but i still couldnt get it to work.

Please Help!