Hi,
SyncAgent.LocalProvider property expects
ClientSyncProvider object reference. In fact, Microsoft deal builtin Client Sync provider for SQL Server Compact but you may create your own provider as well. Here you can see a
SQL Server Express custom provider that shows the way you can use this kind of providers.
In the other hand, you may consider peer to peer approach (aka collaboration scenario). This scenario, which is supported by Sync Services for ADo.NET 2.0, let you decide at runtime, which provider plays as Server or Client, and you can use a couple of SQL Server provider like you do so in off-line scenarios. Can find further information
here.
Hope it helpfull
Best regards,,
José Miguel Torres