EDD displays only checkout button

Hi lads,
I have a trouble with EDD. I tried to add button to one of my pages, but anything what I get it’s just “Checkout” button. For example I used short code (copied from downloads):
[purchase_link id="548" text="Purchase" style="button" color="gray"]

but everything what happens is small button “Checkout”, I suppose settings of the button (color,size, etc) are overwritten by my template, but why I always have only “Checkout”, cannot change text in button. Also this button always redirects me to “Checkout” page. shouldn’t it work as “Add to cart” only?
Please help,
Piotr

http://wordpress.org/extend/plugins/easy-digital-downloads/