We take donations through our website for five different causes which have a matching fund and designation. When a gift comes through TNEW, it is recorded with the correct fund, but the designation is assigned to the designation that is marked as default in the campaign.
This is what I've learned from Support: "Designations are a record of a soft purpose for a contribution and not something that is specified by the API or TNEW so if you are using them, it will have to be a manual adjustment done for order through TNEW. This is one of those things that is only in the applications."
But I'm hoping that someone out there has figured out a fix for this.
Not a "fix" per se, since the software is working as designed, but if there's a 1:1 correspondence between fund and campaign, you could make this happen with a stored procedure running automatically as a SQL agent job. Outside of that, you'd likely need to rethink your campaign or designation structure -- if funds are always matched with the same designation, then could you consider removing the designation entirely and just reporting off of fund? Designations are optional, after all. Or, you could create separate campaigns for each of the five different funds so you could have separate designation configuration for each.