road warrior and id field.

hi
consider the rw config. the responder has the rw conection added while the
initiator has connection with its home adress addded.
then after moving to the foreign network i 'up' the conn at the rw.
i need to negotiate from the foreign network for SA ;s based on home
prefixes. is this possible with freeswan -1.91?

Then the following sequence proceeds.

In RFC 2409 "The Internet Key Exchange (IKE)",
 in 5.1 "IKE Phase 1 Authenticated With Signatures", describing Main
 Mode:

         Initiator                          Responder
        -----------                        -----------
         HDR, SA                     -->
                                     <--    HDR, SA
         HDR, KE, Ni                 -->
                                     <--    HDR, KE, Nr
         HDR*, IDii, [ CERT, ] SIG_I -->
                                     <--    HDR*, IDir, [ CERT, ] SIG_R

my question,
we can send and IDii of a thrid machine in I3 . so refine connection is
used to get the corresponding connection based on the IDii value.
what if there is another connection with the same id value (but the source
and destination addresses in the connection have home prefixes.)
but on what basis will it prefer, the home connection to the rw connection
which also has the same id.?

now the reply- R3should go to back to the initiator. but the sendto()
function used that.host_addr to send to the destination , which has now
been updated with the home address of the rw. shouldnt the reply be sent
back to the source address of the packet?

this way it is not possible to negotiate for an SA having address other
than the addresses of the negotiating machines?
is this conceptually wrong?

your inputs will be appreciated .
thanks and regards