In the absence of replies from those who know NEO2.2 better than I (I use modchip.com on my NTSC PS2), I'd advise in two ways:

1 Wait for the more comprehensive NEO4 (just about due out they claim at playstationmods)

2 Look at www.modchip.com for an alternative

The wisdom on this forum is to use a modchip rather than an external solution as the modchip wires reach all the necessary parts.