In the up position, that blower sure is close to the ground?
That is something I noticed about mine too. My x534 uses the hydraulic lift same as it does for the mower deck. It has enough power to lift the blower, just not enough travel to raise it very high. I played with the adjustment on mine this year when I hooked it up and I could not get it to raise the bottom of the blower more than 5 inches. I'd like to see more but its not possible from what I can see, at least in a stock configuration.
Not sure quite why you need it to lift more, but the reason it can't is probably because the blower drivetrain can't be made to move over that wide a range. I don't know exactly how the PTO to the blower connection works on X5xx tractors, but if there is a U-joint involved they can only handle so far off-axis. That's certainly the case on my 455 - raise the blower too far and it gets very noisy and clearly is putting a lot of stress on things.
Tim