We have purchased a composite USB stack from MicroDigital [login to view URL] and are trying to implement into our STM32 ARM environment but are currently struggling, the example RAM based mass storage device is working, however we are currently unable to convert to using a SD mass storage device. We are looking for someone that has Microcontroller experience with USB to assist us. Ideally someone that has experience with MSD and complex (compbined serial/MSD) devices.