Adding a host-only virtual adapter in VM

Hi,

My setup is as follows.

Host: Vista 32

Guest Ubuntu 12.04 (LTS) 64 bit

I added a host-only virtual adaptor to guest but when I power up the Ubuntu VM the adaptor does not receive an IP from DHCP.  Somewhere

I read that host-only adapters are automatically connected to VMNET1 so my adapter should have received an IP.  Have I misunderstood the documentation?

However if I add a new custom host-only adapter and connect it to VMnet1, from the dropdown list, the adapter gets an IP and all is fine.

So what is the point behind host-only adapters if they're isolated from the system?

Thanks in advance for any help.