The generation works like this:
1) The .NET Framework designer infrastructure serializes the form into a set of CodeDom statements (actually it creates a new class with fields for the controls and a single method: InitializeComponents, and puts the class into a CodeCompileUnit).
2) MergeFormChanges is called on the DesignerGenerator. The implementation AbstractDesignerGenerator uses the CodeDom code generator built into the .NET Framework to generate code in the target language for the InitializeComponents method body.
3) The InitializeComponents method body is replaced with the new body.
4) Fields are added/removed/replaced as required.
If you want to change the code generation, you would have to change the CodeCompileUnit before it is used to generate code in the target language. This could be done inside the AbstractDesignerGenerator.FixGeneratedCode method.