NFC - how to launch the app using NDEF_DISCOVERED

Question

I am writing an application that is supposed to detect nfc tag and automatically be launched. I have succeeded in doing so by using TECH_DISCOVERED + filters but I think the better way to do it is by using NDEF_DISCOVERED. I have added the intent-filter to my manifest but it doesn't work. This is my manifest code for the TECH_DISCOVERED, that works:

    <intent-filter>    
    <action android:name="android.nfc.action.TECH_DISCOVERED"/>
    </intent-filter>
    <meta-data android:name="android.nfc.action.TECH_DISCOVERED"    
     android:resource="@xml/nfc_tech_filter" />

when I want to try the NDEF_DISCOVERED i try:

                <intent-filter>    
                <action android:name="android.nfc.action.NDEF_DISCOVERED"/>
                <category android:name="android.intent.category.DEFAULT"/>
                <data android:mimeType="text/plain" />

for the tags, I use 'Mifare classic 1k' tags that was written as 'Smart Poster' using NFC TagInfo app from the market.

What am I doing wrong? or, what is another way to make my app be launched and not show the activity selection dialog?

Thanks, Eran.