question about swfdotnet - need to add AS code to first frame

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C#

ASP.NET

Hello,

I am using swfdotnet to create swf file from C# code. I am looking for some code that will insert AS code to the first frame. I am creating the swf file using:

Swf swf = new Swf();
swf.Size = new SwfDotNet.IO.Tags.Types.Rect(0, 0, 728 * 20, 90 * 20);
        swf.Tags.Add(new SetBackgroundColorTag(255, 255, 255));
        swf.Tags.Add(new ShowFrameTag());
        swf.Header.Fps = 30;
        
        SwfWriter writer = new SwfWriter(Server.MapPath("~\\Upload\\") + "/" + "newfile.swf");
        writer.Write(swf);
        writer.Close();

and I need to insert some Action Script code to the first keyframe of the first frame. I have the code hold in a string variable (so I dont need to write the code using swfdotnet) i only need to insert the code that in the string variable to the first keyframe. (the swf file is not complicated only 1 layer that include 1 keyframe (for as code) and thats all!!!