Matt,
After much discussion and testing, our superstar Dev (Greg C.) discovered a way for you to map your string values as a constant in the config. He tested with the following and said it works.
{
"direction": "ex2in",
"internal": "contactInfo.phone_work",
"external": "User.TelephoneNumber",
"replace": [
{ "replaceDirection": "ex2in",
"pattern": "^.*$",
"replace": "+61 7 1433 $0" }
]
},
Obviously, you will need to provide the required values for the "replace" string but hopefully this will work and you won't have to populate every user's AD fields.
Let us know if this is successful! :-)