For the feed you need to do that modification to you can register a "Text After" filter against the Buy URL.
From the admin home page, click Filters alongside the feed; then using the form to add a new filter select "Text After" and choose the Buy URL field. You can then enter the text you need to append to the Buy URL in a text box. You will need to re-import the feed for the changes to take effect.
Hi,
For the feed you need to do that modification to you can register a "Text After" filter against the Buy URL.
From the admin home page, click Filters alongside the feed; then using the form to add a new filter select "Text After" and choose the Buy URL field. You can then enter the text you need to append to the Buy URL in a text box. You will need to re-import the feed for the changes to take effect.
Hope this helps!
David.