I'm developing a NFC application intended to register the attendance at conferences.

In a ubiquitous computing environment, we need to run the MIDlet automatically when the mobil touches the reader, in order to avoid starting the MIDlet manually by the user.

I've been reading docs spreaded over Inet and I think a probably way to achieve it as follows:

The Secure Element (SE) acting as a external card (java card, with a signed applet inside)
The reader reads some data (ie: login, pass), from the SE and writes some dummy data (for example a time stamp, I don't know if this is really needed).
The SE invokes o sends a signal to the MIDlet via the PushRegistry
The MIDlet speaks with the reader (this time using NFCIP for example), acting as initiator.

I think the correct permissions in the JAD could be very similar to this:
MIDlet-Permissions: javax.microedition.apdu.aid, javax.microedition.apdu.sat, javax.microedition.io.PushRegistry
MIDlet-Push-1: secure-element:?aid=<MIDlet AID>,>MIDlet_name>,*

And so far, I'm wondering if there is another way to achieve the automatic starting of the MIDlet
(and avoiding this way buying an expensive certificate for code signing)

I don't know if the pushregistry works with a different protocol to achieve that. Could anybody explain me anything about it??

Any help would be appreciated.