Second part of this question often includes:  If so, do I then append the invoice with activity as we go along to cause the number to become less negative as the client uses up the retainer? 

Yes. If the files are not invoiced, they will not show on the report. When you enter a retainer, you will want to invoice the file after you have completed it. That way it shows the balance remaining on the file or what is left of the retainer.

What you can do is use the system Tags. If you create a Tag and name it "Retainer", you can then add the "retainer" tag in the file. You will then be able to search for all files with the tag "Retainer".

1. To create the Tag go to settings>Case Management>Tags
2. Select the green "add tag" button at the top of the page.
3. Label the tag "Retainer" and choose the color you want the tag to show as.
4. Then go to settings>Case Management>Case Type
5. Select the edit icon next to the case type.
6. Where you see "tag" add in the Retainer tag you just created and hit submit. You will need to go this for all case types to be able to use the tags in all your files.
7. After you add the retainer tag on the case details page of the file, you will then be able to search for all files tagged "retainer" in the search page or on the Dashboard.