If I understand what you are trying to ask is how to get the address of the device back to your server-side push initiator application.
If so, you can see an example here:
https://developer.blackberry.com/java/documentation/registering_to_receive_push_messages.html
Basically you can see the sample code for the sample push-enabled application constructs an HTTP message to send to it's server-side application. While this sample does send the HTTP message in the format the SDK expects you don't need to use the SDK or the same format but you can follow the example to send a simple HTTP message to your own server to pass the information your server-side app needs. For example, the link above shows that to get the device address you can do this:
Integer.toHexString( DeviceInfo.getDeviceId() )
In your server-side application you should save that device address and then when you construct the push request message you use it as the device address if using the SDK low-level APIs (or insert that value in the address field of the PAP XML if not using the SDK).
