Finally I could get the installation to the end, but there is one more
problem. I selected the generic kernel, and some other common sets, the
process of extrating goes well but once I reboot, the booting message screen
freezes at some point (I tried it several times and it freezes at diferent
points, mostly after the line concerning the internal modem), I then tried a
new install selecting this time the laptop kernel (after all this is a
laptop) and it freezes at some other point. In both cases it freezes to
the point that not even a hard reset will do, so I have to unplug the
battery and plug it back again to be able to reboot.
This is the last line in the booting secuence most of the times:

Intel 82801ca/cam Modem (modem comunications, revision 0x02) at pci0 dev 31
function 6 not configured
isa0 at pcib0

Lastly, I tried the tiny kernel and the booting process finishes without
any problem giving me the login prompt and sugesting that neither the
generic
netbsd kernel, nor the laptop kernel can detect or understand all my
hardware.
There are still two more kernels left, PS2 and Diagnostic, but I don't know
if those would make a diference.
Is there a solution for this case? I could use the tiny kernel,
but I know it will be very limited, I guess there will be no network or X
server possibilities with it (tried xf86config with tiny K, but I got the
expected error message: "no core support"). And as my intencion is to use
NetBSD regularly (plan to install apache, some database, php, perhaps a
window manager, etc, etc), I think a limited kernel won't be of much use.
Any sugestions ?