Paypal Button Item Name?

ok heres the code i’ve been using for my paypal buttons on my flash sites.
not the only thing is i put my item Name in the “item_number=” and for some reason i need to put underscores or someting, it wont work it i put spaces in between the words of the item name, and it i put the code in for a non-breaking space it makes the word before that code the only word you see in the paypal cart page in the desciption.
So ive been doing this This_New_DVD (thats what the item name looks like in the paypal cart description section.
anyone know a solution?
am i even doing this right?

on (release) {
getURL(“https://www.paypal.com/cart/add=1&business=MyPayPalEmailAddress&ItemQuickname=Shopping+Cart+Button&item_number=ITEM_NAME&amount=19.95&page_style=MyPayPalStyle&shipping=4.00&shipping2=0.00&handling=0.00&return=http://www.paypal.com&cancel_return=http://www.paypa”, _paypal);
}