Hey Sixto,
Got the same "problem". And I saw more 603's leaking there.
At my IP it is really a very little leak : I clean it once a week and the IP stays dry at the exterior ( and I am driving 800km a week ).
But I should like to fix it anyway : it's the only place / item leaking on my 603 so...
Would you not take in consideration to replace the O-ring? It is not because it's looking OK that it is still sealing up!
Let us know your sollution!
Danny