Cisco CCIE Certification and CCNP Certification FAQs :
Why doesn't IS-IS work in a hub and spoke configuration?
There must be a full mesh for this to work, you could connect R1 to R2 with a tunnel and run an adjacency over this.
You could also originate a default route into the other areas, but this won't always work.
Date: 2003-12-04 16:25 -600
IS-IS does not run over logical hub-and-spoke. You'll need to
create two point to point IP subnets either by readdressing the cloud or
adding GRE tunnels.
...
By logical I mean one IP logical subnet. There is no problem with
physical hub-and-spoke circuits. The easiest way to avoid the many problems
that logical hub and spoke brings with it is to use point-to-point IP
subnets. Simply create a point-to-point subinterface for each circuit that
you have.
Date: 2003-12-04 14:32 -600
THis link has the command you need.
12.2(8)
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122t/122t8/ftissp2p.htm#1026660
You can also use tunnels to solve the problem if the above is not allowed.
Why don't the other interface addresses show up when redistributing into ISIS?