um_profile_field_filter_hook

Hi,
I would like to add a filter function to encode email adresses on the front page.

When I hack it into your plugin souce file um-filters-fields.php it works:
function um_profile_field_filter_hook__( $value, $data, $type = ” ) {
…
if ( !is_array( $value ) ) {
if ( is_email( $value ) )
$value = ‘<\A…>’.eae_encode_emails($value).'</\A>’;

I tried then to do it the clean way and add the filter but don’t succeed:

function my_profile_field( $value, $data ) {
return eae_encode_emails($value);
}
add_filter( ‘um_profile_field_filter_hook__user_email’, array( $this, ‘my_profile_field’), 10, 2 );

Any tip what I am doing wrong?
Thx,
Axel