You can hack the process by having a database update trigger revert any value at update.
This would mean that you could setup a UserCreated field as an audit value. The initial insert would be populated with the username. Any updates to that column would be reversed by the trigger.
An update trigger to ignore the field change would be...
CREATE TRIGGER [SalesLT].[trig_Customer_Update]
ON [SalesLT].[Customer] AFTER UPDATE
SET NOCOUNT ON;
SET UserCreated = D.UserCreated
FROM [SalesLT].[Customer] C
JOIN INSERTED I on I.CustomerID = C.CustomerID
JOIN DELETED D on D.CustomerID = C.CustomerID
WHERE I.UserCreated <> D.UserCreated
OR (I.UserCreated is null and D.UserCreated IS not null)
OR (I.UserCreated IS not null and D.UserCreated IS null);
Let me know you know if you find an easier way to ignore/revert field updates in a trigger.