[TYPO3-mvc] Extending fe_groups - creating fe_groups in FE?

[David Effendi]

Hi Folks,

I'm currently trying to get an extension with extbase and fluid running
and I'm stuck.

I extended the fe_groups table - successfully added all fields to TCA
and can access all fields incl. my extended in the BE & FE. In the
Frontend I can list all fe_groups which have been created in the Backend.

But I just cannot create a new group in FE. The "new" Form is being 
displayed and I can sned the form - it is even redirected back to the 
index - but no db entry... :(

I suppose a fe_group record can be added in FE?
Or did I miss something here?

I'm also not realy sure about the TS setup. Where do I have to use which 
variant (UpperCamelCase, etc.) ?

My TS setup:
config.tx_extbase {
	persistence{
		classes {
		    Tx_Myext_Domain_Model_Group {
		        mapping {
		            tableName = fe_groups
           			columns {
				tx_myext_pi1_image.mapOnProperty = image
				...
	                    } 		
		        }
		    }
		}
	}
}

In all the threads I've been reading so far all plugin TS conf was like 
this:

"plugin.tx_myext{ ... }".

But
In my ext_localconf.php I have the following:
Tx_Extbase_Utility_Extension::configurePlugin(
	$_EXTKEY,
	'Pi1',
	array(
		'Group' => 'index,new,edit',
	)
);

In my ext_tables.php this:
/**
  * Registers a Plugin to be listed in the Backend. You also have to 
configure the Dispatcher in ext_localconf.php.
  */
Tx_Extbase_Utility_Extension::registerPlugin(
	$_EXTKEY,
	'Pi1',	// A unique name of the plugin in UpperCamelCase
	'my ext name'// A title shown in the backend dropdown field
);

When I place the plugin on some page the name of the plugin becomes 
myext_pi1. So do I have to configure my plugin this way:

plugin.myext_pi1{ ... }  ?

Anyway I've tried both with no results.

Me no see the forest caus of all of the trees!(like germans like to say :P )

I'd be very grateful for any help on this!

Thank you for your suggestions in advance,

David