We're in a bit of a catch-22. The Firebird ADO.NET provider's schemas for meta-data don't contain package information in the procedure parameters schema. This is problematic as in the situation where you have a proc Foo in a package and without a package, you'll get all parameters of both for 'Foo' and there's no package name in the set of meta-data.
We can query it ourselves, however the information we get back lacks type information, as the ADO.NET provider performs excessive type information processing before it returns the meta-data schema. The only 'solution' is to copy the code but as it's not a simple small function, this is a no-go. We could call into the Firebird ado.net provider but that requires is to take a hard-reference on the provider which is something we don't want to do either (as that has bitten us in the past).
So currently we can't determine the parameters for packaged procedures. We hope to find a solution for this, otherwise we sadly have to postpone this feature till the ado.net provider does contain package information.