How to add aditional filetype icons??

By default, FileVistaControl show filetype icons for wellknown filetypes like ZIP, RAR, AVI, MOV, JPG, PDF, etc.
I'd like to add filetype icons for FLV, PS, etc. 
How can I do that??

Eric

Adding new filetype icons is very easy, just put PNG (16x16) images to the folder FileVistaControl\images\fileicons with the names in format EXTENSION.PNG. Then restart the appdomain (by saving web.config) so that the control checks and loads the new images.

Is there a way to do this with the FileUltimate control?  I want to have an icon for .lnk file types.  I created GleamTech.FileUltimate\images\fileicons\lnk.png and then saved the web.config.  But it doesn't change anything.

Thanks for any advice.