(keitai-l) Sharing E-Mobile Connection?

Hi all,

Any ideas about how one might go about sharing an E-Mobile connection?

Been using E-Mobile HSDPA for a while now and am very happy with it.   
Occasionally, it would be useful to be able to share the connection  
with a second laptop.  Normally, this would be easy using something  
like the built-in NAT router on Mac OS X -- and this has worked in  
the past (albeit painfully) using an EDGE phone connected via  
Bluetooth.  But for some reason E-Mobile seems to be smart enough to  
drop packets originating behind a NAT router or something.

I guess it's reasonable for them to have such a limitation.  But I'm  
not looking to run a hotspot or even a home network off the  
connection -- just would like to avoid swapping the USB modem back  
and forth when I'm out with a friend with a laptop.  And I'm sure I'm  
one of their "lighter" users in terms of bandwidth usage.

I tried tunnelling over a VPN, but the NAT router on Mac OS X seems  
to run below the VPN level.  There's got to be some other workaround  
involving tunnelling or encryption...

Any ideas for a workaround?

Thanks in advance!


-----
Joseph Luk
Nara, Japan