Hallo! I switch back in english =/
I've found a notation for aaaaall the surrender variations that can existed xD
It will be a bit difficult to explain it, but I will try.
To begin, I try to develop a bit this concept, with an inverse sonic 12-2L1-1L1 (an inverse sonic which begins in the Right Hand, in 12, and which finishes between the index of the Right Hand, and the one of the Left Hand).
And I find that everything was in the relative positions of the two hand. I made a video on this, to be more precise:
http://www.youtube.com/watch?v=5FjvBVrIw1g
This is the summary:
To describe the position of the two hands, we have
(PD // PD) The Left hand in palm down, parallel to the Right Hand in palm down
(PU // PD) The Left hand in palm up, paralell to the Right Hand in palm down
(PD >< PD) The Left hand in palm down, opposed to the Right Hand in palm down
(PU >< PD) The Left hand in palm up, opposed to the Right Hand in palm down
(PD // PU) The Left hand in palm down, parallel to the Right Hand in palm up
(PU // PU) The Left hand in palm up, paralell to the Right Hand in palm up
(PD >< PU) The Left hand in palm down, opposed to the Right Hand in palm up
(PU >< PU) The Left hand in palm up, opposed to the Right Hand in palm up
And for the fingers' notation: The hand in which the pen start has the same notation as usual (fingers = T 1 2 3 4). The slots are the same as well (12, 23...). The only changes are for the fingers of the other hand, we precise to which hand he belongs with the letter of his hand: "L" for Left and "R" for Right.
I take the exemple of the "surrender sonic", it becomes:
(PU >< PU) (or (PS >< PS) for palm side) sonic 12-1L4
As for a sonic 23-12, the position 13 is not written, the position "2L4" of the sonic 12-L4 is not written.
This new notation permit to breakdown the transfert from one hand to an other: A backaround which begins from the Right Hand in 12, to the left hand in 12 can be written like this:
(PD // PD) Backaround 12-L(12)
With brackets to be more precised
And this notation permit to discover other transfert! for exemple:
(PU >< PD) Backaround 12-L(12)
Or (PU // PD) Backaround 12-L(12)
I'm waiting for your comments =p