User profile sync with AD and custom provider

Question

This is kind of sequel for [question]: How to bulk import User Profiles from a legacy system and pre-create MySites. After research I went with next strategy:

1. Part of users in new system will be UProfile synchronized via AD sync (this is ok and working)
2. Part of users which aren't in AD I would like to be be UProfile synchronized via BDC which will use custom profile provider (this is neccessary because they have some authentication system for internet users which MUST be used but which can provide us standard information about that kind of users).

Questions:

1. Is part 2 feasible (is it possible to do that)?
2. What should be steps for that part? (I assume that I should write custom provider and after that to create BDC WCF service which should use my custom profile provider to retrieve user informations from auth system, and after that to create BDC UP sync connection to my WCF service)? Is that right?
3. Any comment or maybe sceptical thought?

Answer 1

You can do this, feasible or not. Check out my (former) colleagues answer here on how to do this. Not sure about if BCS (BDC was the name in SP2007) would be possible, I know my colleague didnt use BCS fields so you would have to do a POC on that if you want to extract data from a secondary data source.

Another approach would be to create a flat file and do an LDIF import.