At first thought the only way I can think of this working is to modify the templates, both the sprocs that are generated and the code that passes values to the sprocs. For migrating data if you have access to Sql Server Integration Services I would recommend it as that is what it is designed for. Our company has gone both routes in the past and prefer SSIS over .netTiers for migrating data both because it is faster at processing records, and it has various tools built in that handle migration scenarios like keeping the identity value.
Edit: I should be more specific, SSIS comes with SQL Server 2005.