Avamar Retention/Schedule

I am setting up Avamar for our environment and am running into a potential issue. At the beginning (and end) of our nightly processing we need to run backups of our administration server. Because the start and end of our cycle can vary depending on whether the cycle is a normal daily, a longer running daily (after a weekend), or a month-end we need this backup to be started manually. I need to have the following retention on these backups:

Daily: 3 weeks

Monthly: 1 year

Year End: 7 years

Looking at the documentation for Avamar you can't specify a retention period on an on-demand backup because it doesn't know about daily, monthly, or yearly backups. I did figure out though that if I create a policy with a schedule that was configured to be "on-demand" I can also specify the retention policy that I created for this type of backup. What I'm not sure of is if this will apply the appropriate retention periods since the schedule is still an on-demand backup.

I'm new to Avamar so I'm looking for the best way to achieve what I'm after. Any suggestions are greatly appreciated.

Thanks.