welcome to the Roland club.
I made another post where I advised I had bought adapter and CF card for my E 80 so look through the posts here and also some in the General arranger forum.
I bought mine at: http://www.outpost.com/
they have the bigest stores here in silicone valey and in several other states and now on line also. they have everything and at the most competative prices.
I peeked into your website and I see you have a ton of gear like I do. I am thinking of a sale soon. Getting crowded in here
Enjoy your E 50 and let me know if you want to be on my Roland E and G mailing list.
also note that there are updates available for the E 50 OS.
Best to you and yours,