It's been long enough since v12 that I don't remember precisely how Add-On Profiles work with that software. I don't have a computer, even a virtual machine, with v12.
In general, if you need to create an I/O tree object with a PowerFlex whose module profile was not included in the RSLogix 5000 release you are running, you install an "Add On Profile".
AOPs are different from Electronic Data Sheets; they are more complex and often include a sort of "plug in" software object to configure a complex device. In the case of drives, it's an embedded version of DriveTools.
Unfortunately this morning the main Knowledgebase is down (not a common event). But the Product Compatibility and Download Center appears to be running.
https://compatibility.rockwellautomation.com/
You can click on the "Add On Profiles" in the Quick Links section, then sign in with your account credentials.
The AOP download section has no sophisticated search system; you literally have to Control-F to search the long column. "PowerFlex 4-Class & 7-Class, SCANport v4.09.00" is what you're looking for.
The release notes for that AOP suggest that it includes support for PowerFlex 700 Vector (the 700VC) with 20-Comm-C but doesn't specify which firmware revisions.
Select the checkbox for that AOP, and click the "Download Now" button at the top of the page, and follow the prompts to download that ZIP file of about 720 MB.
AOPs install with their own installer. Shut down all your Rockwell software, unzip that file, and execute the setup.exe installer.