Motorola SM56 modem setup soft-hangs

Motorola SM56 modem OEM driver setup (setupapi-based), which is supposed to just copy a driver and copy/register a service, hangs in progress. One can try to install the driver without it and it wouldn't work either though, well, because it's a modem driver...
Real hardware, ASUS M51Vr, tested on bootcd-r71090(rosbe).iso and for many revisions before.
this part is where it stops

WARNING: calling stub SetupQueryInfVersionInformationW()

(../../dll/win32/kernel32/client/except.c:387) Missing function in   : setupapi.dll

(../../dll/win32/kernel32/client/except.c:388) with the functionname : SetupQueryInfVersionInformationW

err:(../../win32ss/user/user32/windows/message.c:1506) Exception when calling unicode WndProc 0041ADFF Msg 1025 pti B6763300 Wndpti B6763300