You can create an SvcV-2 just before finishing an OV-2 or in later stages of the architecture just before finishing the SV-1 or SV-2 views.
To create a SvcV-2 diagram
Create Service Accesses.
Associate Service Accesses using Resource Interfaces.
Create Resource Interactions flowing via Resource Interfaces.
You can model each Service Access internal structure using the SvcV-2 Services Resource Flow Internal Description diagram or in a special structure compartment of this element shape.
Info
You can proceed to create SvcV-4 view as soon as the SvcV-2 has been completed.