Returned variables

Trying to switch over to using SOAP because of using a new payment processor

Currently using PHP code and Curl to interact with PayPal, but SOAP is new to me.

How do I send variables in the SOAP request and use them in my return code to

be processed on my end.

Here is a sample of what I send to PayPal:

<input type='hidden' name='custom' value='$affiliate::$sponsor::$sponsor_email::$lang::".$order->user_email."::Raffle Ticket::".$order->order_tickets_nr."::$bevent::$rep::$card::$local_amount::$local_currency'>

When these variables are returned, my code separates them by :: and they are processed on my end.

How do I send all these variables in the SOAP request, and separate them when returned?

Our new payment processor has a field called 'returnContext' and looks like the format would be

'returnContext'=>'test=2&ok=1&oui=2'

So I need to put:

variable name=variable value&variable name=variable value&variable name=variable value ??

Then how to use them when returned....

Thanks for any input....