I am just tring out how to run FLV files on a my blog. I have tried with this video "How to Write Extensions for BlogEngine.Net"
Watch this, now its working, it gives new life to the blog generation.
Installation
Download the zip. Unzip using any archive manager. At the top of unzipped package you should have two items: "flv" folder and "flvplayer.cs" file. Copy flvplayer.cs into your BlogEngine extensions directory (/App_Code/Extensions). Copy "flv" folder with all it content into root of your BlogEngine application - this is where you'll upload your flv files for embedding also. More...