questions about installation options

[Praude]

I'm planing to do a clean install of "Suse 10 perfect setup" using a 64bit version.
I was trying debian but i thoght it was a shame to be running a 32 bit system in a Athlon 64 X2 and I didn't get the hang of debian very well.
Since I'm more familiar with suse I'll switch back to it, I read the newst version of ISPConfig now installs on a SUSE x86-64 without having to manually edit anything.

I have some (really dumb) questions about the ISPConfig instalation
but In doubt, I rather ask and make things right:

on SETP 7 and STEP 8
Encrypt the private key now? [Y/n]:
Do I have to choose "No" so the server can be restarted without human intervention? I remember it mentioning something in the earlier versions about this so i'm not sure

Please enter the IP address of the ISPConfig web (e.g. 192.168.0.1):

should I use the server ip (e.g. 192.168.123.x) or the router ip (e.g. 200.175.x.x) ?
The server is behind a router as a dmz host and everithing gets fowarded to it

Please enter the host name (e.g. www):
Please enter the domain (e.g. xyz.de):

the only registered domain I have right now (praude.eti.br) is already hosted somewherelse, and is has the following hosts "www" "ftp" "mail" configured at that site.
Can I use "serverX" for the ISPConfig host (localmachine host name) and praude.eti.br (localdomain)? and later setup dns records pointing serverX.praude.eti.br to the router IP wich ISPConfig machine stands behind
Or shoud I just leave host blank and use the router ip (e.g. 200.175.x.x)? what would be best ?

Thanks in advance for any help