In a saucepan over medium heat, soften the onion, jalapeños and ginger in the oil. Season with salt and pepper. Add the pumpkin and mushrooms and sauté for 2 minutes. Season with salt. Deglaze the saucepan with the vinegar. Add the broth, tofu and soy sauce. Bring to a boil. Reduce the heat, cover and simmer gently until the pumpkin is tender, about 25 minutes. Add the lime juice and adjust the seasoning.