HSRP: private IP on interface, official IP as standby IP

[XeROnetwork]

With HSRP configured on two 7204VXR routers, I'm trying to find out if it is really necessary to have IPs from the same net configured as the interface IP and standby IP?

For example with this setup:

interface GigabitEthernet0/1

ip address 10.0.0.1 255.255.255.240

standby 0 ip <official-ip>

I'm not able to ping the official IP on the router itself. Although the standby group is up and running fine and the standby IP is present in the arp cache:

Internet <official-ip> - 0000.0c07.ac00 ARPA GigabitEthernet0/1

Any BGP session on this link is torn down after a while.

But this is working fine:

interface GigabitEthernet0/1

ip address <official-ip + 1> 255.255.255.240

standby 1 ip <official-ip>

Ping is working from anywhere.

I wouldn't want to "waste" 3 IP addresses in each net just because of HSRP.

Is there any way to do this with private IPs?

Regards,

Lars

[XeROnetwork]

Right after postings this it came into my mind, that I didn't have a static route defined for the net that the official ip belongs to. All of a sudden it was working, of course. ;)