Take a look at those two links:
Implicitly, they state that Imaging should be installed first ("you could extend an Imaging domain to include Oracle SOA Suite"), but SOA should be started first ("you need to start the Oracle SOA Suite or Oracle BAM Managed Server before you start the WebCenter Content Managed Server"). No further facts explained.
If I were you I'd create two domains. It might require some extra works (e.g. using a separate stand-alone LDAP rather than the integrated one), but it will prevent future issues.
Thanks a lot Jiri,
But I'm not speaking about Imaging. Imaging (IPM) is already present in my domain. I'm extending the domain with Capture Server.
And It really looks like there is some sort of conflict between Capture Server and existing SOA Server because:
1] Before Extending the Domain with capture server, I start the Admin Server, I log in to the EM Console and I see all the SOA Applications listed there.
2] After Extending the Domain with capture server, I start the admin server. Then 1st thing I start after this is soa server (as you said). This fails. And in the EM console I no more see SOA Applications.
What I can conclude from this is, there could possibly a conflict between soa and capture servers when capture server is installed on existing soa server (may not be the case if soa is installed later.)