Attribute add to cart url

[Endre]

Hi, everyone.
Have searched the foum extensively, but cannot find the answer to my problem.
Is it possible to add a product with a certain attribute directly to the cart, from a newsletter for instance?
I know what to do when the product has no attributes, but I can't figure out how to find the url for a product with attributes.
For instance if I send a newsletter to my customers, I want the "Buy now" button to add a product with a specific attribute to the cart directly, i.e A road bike in size large.
How can I do this?

Cheers
Endre

[Endre]

Nobody knows the answer to this?
Has to be a combination of product id and option value of some sort.
Any help would be greatly appriciated.

Cheers
Endre