On the BA-5D, pin 40 traces through one resistor (r377) and a coil, L304, then to a jumper.
On 5A-5, Pin40 (ys2, blanking) traces through R263,then through what looks to be marked R337 AND C026 before hitting a jumper right next to c026. I don't know enough about electronics to give you any feedback as to how many ohms your blanking wire would be. But I'd always prefer to go in through a jumper if at all possible. Makes life so easy.
MARKOZLAD: can you give any feedback as to whether that jumper can be used, and what needs to be added to the 5v to use it?

Note:
R263 is 100ohm resistor
R337 is 2.2kohm resistor
Being that 2.2kohm is exactly what i used for my 5v/blanking line, does that mean he can just inject a 5v source directly to the jumper in the image above?
However, on the bright side, the jumpers for R, G, and B are directly next to the jumper for your blanking wire, so that makes that pretty damn easy.
For 2: Not sure, as I'm from the US and not that familiar with SCART. I don't know why you'd want/need composite video if you're doing RGB, unless composite video input carries CSYNC, then I'd say yes, that'll work, and looks correct.
For 3: Correct, if you are using the mod board design I did.
For 4: That is correct, yes. YOU are controlling blanking on this TV with the SPST switch.