java - How can I pass request parameters along with pay key in pay pal adaptive embedded payments? -

i using light browser embedded application. have form has action set "https://www.sandbox.paypal.com/webapps/adaptivepayment/flow/pay".

i have java script triggers pay pal pay button.

<script type="text/javascript" charset="utf-8">   var embeddedppflow = new paypal.apps.dgflow({trigger: 'submitbtn'}); </script> 

now inside form have pay button , input parameters set shown below. have input parameters "exptype", "paykey" , "custom".

<input type="image" id="submitbtn" value="pay paypal" src="https://www.paypalobjects.com/en_us/i/btn/btn_paynowcc_lg.gif"> <input id="type" type="hidden" name="exptype" value="light"> <input id="paykey" type="hidden" name="paykey" value='<%=request.getattribute("paykey")%>'> <input id="custom" type="hidden" name="custom" value='<%=(string)request.getattribute("custom")%>'> 

but once after payment occurs , when asynchronous request ipn notification url regarding confirmation of payment, seeing null "custom" have passed 1 of input parameters. can 1 please advice there way around in passing additional request parameter in adaptive(chained payment) embedded payment?

well, there no way directly can pass additional input parameter other pay key in adaptive payment. that's have found. work around using payrequest object , set parameter trackingid.

payrequest payrequest = new payrequest(); payrequest.settrackingid("set parameter this");

use trackingid retrieve in ipn.