How to use Structured Output with gemini in VertexAI

Hi! We are trying to implement for Gemini models deployed in Vertex the new functionality of native structured output with the ProviderStrategy but we are getting validation errors and we think it is because ProviderStrategy is hardcoded for OpenAI. Has anybody found a workaround or does anybody think we are maybe using something wrong? With ToolStrategy it is already working but since the ProviderStrategy is preferable we wanted to migrate to that