Instead of using our standard Aweber integration method which depends on the buyer deliberately opting-in, a more reliable solution would use the Payment Variable Information URL setting to send the order data to the URL of a custom script on your own server, which would then submit the buyer's info to Aweber. If you would need some help setting that up, we can recommend the competent, E-junkie-experienced developers listed in our directory here:
http://www.e-junkie.com/ej/developer-directory.htm
As another alternative, have you considered using some combination of our Thank-you Email and/or Send Stored/Generated Codes features, to provide buyers with the call-in number and pass-code as soon as their payment is completed?
http://www.e-junkie.com/ej/help.custom.thankyou-email.htm
http://www.e-junkie.com/ej/help.selling-codes.htm
If you want to continue trying to use our standard Aweber integration, you could add some custom text to the shopping cart, explaining to buyers that they must check the "Sign-up for product updates and newsletter" box during checkout. Just add the following lines to your View Cart code on every page, just before the "// -->" line in the standard code you obtained from Seller Admin:
function EJEJC_config() {
EJEJC_POSTCALL=true;
}
function EJEJC_shown() {
jQuery("#tdPmnt").attr("innerHTML",
"<b>NOTE:</b> You <b>must</b> check the <i>Sign-up for product updates and newsletter</i> box during checkout in order to receive instructions to access your seminar!");
}