Programmatically add user to Membership Schema

I have created the Membership Schema in my SQL Server using the following tutorial.
http://www.asp.net/learn/security/tutorial-04-vb.aspx

I have another SQL database in which I have all the usernames and passwords in clear text.
How do I transfer them into aspnet_users table that uses "Hashed" or "Encrypted" Storage Technique for passwords?
Is it possible to do it using an "Append Query"?

Thanks in advance
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