Property "PaymentMethod" does not have corresponding setter in class "Magento\Quote\Api\Data\PaymentInterface

[esilvajr]

When i'll place a order with REST API (/carts/mine/set-payment-information) i got this error:

message: "Property "PaymentMethod" does not have corresponding setter in class "Magento\Quote\Api\Data\PaymentInterface"."
trace: "#0 /var/www/html/stg1.magento-srv.host.local/public_html/2.0.0/lib/internal/Magento/Framework/Reflection/TypeProcessor.php(591)

payload = {
paymentMethod: {
method: "MyModule",
},
cartId: quote.getQuoteId(),
billingAddress: quote.billingAddress()
};

placeOrder(payload, this.messageContainer);

Anyone can help me?