how to deploy C# solution

I’m using a map with scripting functoids that has external assemblies (a C# class file that treats the messages!)
When I build the project I get no errors, the when I try to \”test map\” I’m getting this error (on all 7 scripting functois):

Error 11 The external assembly with the fully qualified name \”ECIReferences, Version=1.0.0.0, Culture=neutral, PublicKeyToken=2cb9788fe5331215\” cannot be invoked. Make sure this assembly is in GAC. C:\\ECI\\ECI\\EDI2XML\\ECIMap.btm

I think I need to deploy the C# project, so that GAC recognizes the C# class file that I invoke in the scripting functoids. But I don’t konw how!! 😕