The callback system is event driven, so if the triggering event has already happened before the dependent job is submitted, the callback will never be triggered.
Are you building your jobs with the api? Then it's easy:
You need to submit both jobs at the same time so they belong to the same pgrp. Read the "callbacks" section in the Developement.pdf guide, and pay attention to job "labels". When you submit multiple jobs in the same operation, they belong to the same 'pgrp', and any job in a pgrp can reference other jobs in the same pgrp by label; you don't need the jobid. Labels are scoped within a prgrp; they only have to be unique within a pgrp, so you can use the same simple label (like "render") over and over in different pgrp's.
Build the first job, assign it's 'label' attribute a name of some some, a single simple word (no spaces, punctation, etc.). keep it simple but descriptive, say
renderJob['label'] = 'render'
the rvio job should have a dependency that looks like:
rvioJob['dependency'] = 'link-complete-job-render'
Thens submit the jobs in a single list:
qb.submit([renderJob, rvioJob])
You're now guaranteed that the first job won't be complete before the second job is submitted.
The "link-complete-job" syntax means that the rvio job won't start until the ~entire~ render is complete. If you would like each frame's rvio comp to run when the corresponding frame's render is complete, change the dependency to look like:
rvioJob['dependency'] = 'link-complete-work-render'