setting up free busy between exchnage 2010 and 2007 using availibility address space

Dear All,

I am planning to setup free busy between two exchange forests name source.local and target.local. Source.local has SMTP addresses e.g. company1.com and target.local has company2.com With below command shell.

Add-AvailabilityAddressSpace -ForestName target.local-AccessMethod PerUserFB -UseServiceAccount $true

My concern is below.

1. Do I need to add company1.com in the command shell or only target.local domain name only?

2. If i add the availability address space for target domain as target.local, how exchange server will identify where my request will go for company2.com email address.

Thanks for you quick response..

Satpal Kataria