The paypal recipes is a Dreamweaver extension, it cannot be used with Expression Web.
To Add options to your product, you need to edit the form that is created for the paypal button.
an option is passed using two form elements. The first form element is the name of the option "Size", or "Color" the second form element passes the value for the options.
the first form element will be a hidden element. the naming convention to use for the hidden element will be "on<int>" where <int> is a whole number from 0 to 6:
<input name="on0" type="hidden" id="on0" value="Color" />
now we need to create a select list for the option values. the naming convention to use for the option values is "os<int>" where <int> is a whole number from 0 to 6:
<select name="os0" id="os0">
you can have up to 7 options for a product. each name and value form element pair, must use a unique number "on1" and "os1" for the second one, "on2" and "os2" for the third and so on.