If you want the values to survive a profile update (which, as you noticed, involves an actual delete+import, with the 'delete' part being the problem) then you have to implement your own storage scheme
The easiest way to do this is by using the "read/write text to a file" actions, but it might get a bit messy if there are many values you need to store... a more complex alternative, but with more control, is by using a plugin or the new Inline Functions of the latest betas