Is it possible to upgrade my Time Capsule hard disk and keep the backup(s) from the original? Can I upgrade my Time Capsule to a larger internal drive and keep my original backup(s)?

I'm aware you can drop in the new disk, the restore it as a new TC using AirPort Utility, and I'm also aware you can migrate backup(s) from an existing TimeMachine drive to a new one - but I want to do both: I want to replace the 500gb drive in my Time Capsule (2nd gen, 2009) to a 1tb drive, and I want to keep the existing backup(s) from the 500gb to the new drive, so everything is as it was, just with a larger internal drive. 

I understand it's not as simple as swapping the drive, restoring it as a new TC and then using CCC to copy the data from the original drive, so is there a solution to what I want to achieve? Basically I want to upgrade the original TC drive to a larger one and not lose my previous backup(s).
This is achievable for sure. 

First, you need to transfer files and then change your HDD.

This Apple tutorial shows how to transfer the Time Machine backups. 
Transfer Time Machine backups from one backup disk to another

Here in this iFixit link, it's a how-to tutorial for the HDD Replacement. 
Apple Time Capsule Model A1302 Hard Drive Replacement 

I hope you get it done!