that download button is some custom work that this user made for himself (it's a custom work...)

do add a skin: you need to download a skin from longtail video's site: http://www.longtailvideo.com/addons/skins

and then place the ZIP file into the folder /plugins/muscolplayers/jwplayer/skins/ folder
then, on the plugin configuration, just type the name of the skin (that is, the name of the file, WITHOUT the .zip)

thank you, could you do the custom work for download option?
how much?

yes we could develope such a thing. for custom coding work, please contact is directly at joomlamusicsolutions@gmail.com

I understand you want a pretty similar functionality. please, specify as much as you can the requirements on your email so we can make an accurate quote!

also there is now skins folder in my player folder

if it's not there, you can just create it. it's strange that is not there, though..