Question about replication and guids.

We have our own replication schema that works on our fox databases. We are moving to Sql Server. Our replication is similar to merge replication and so we are thinking we will use Sql replication. It is my understanding that Sql needs guids to perform replication. We currently store our candidate/foreign keys ( surrogates ) as unique integers ( unique in our world ) and are wondering if we indeed need to convert them to guids. It is my understanding that if you do not have a guid column sql will create one to use.

My questions are:

1. Is letting Sql create its own guid columns and us stay with integer keys feasible and what are ramifications?
2. Does Sql create corresponding foreign key guid columns as well and resolve the links for us?
3. If Sql creates the guids are they populated by the server on inserts or do we have to do it via triggers/constraints/rules? Or are the columns only created during a replication and then dropped ( not sure if that would even work )? I am not versed on the technical aspects of replication yet.

Thanks a bunch,

Michael