User defined type without single quotes

Hello.
I defined a new type to represent an unsigned int, but when I try do run a
query it complains because it is not quoted and casted to my type.

Suppose I have a table:

-- my_uint32 is my new type
CREATE TABLE test (a my_uin32);

If I try to run this insert, postgres complain about the type:
INSERT INTO teste (a) VALUES (10);

But this one works:
NSERT INTO teste (a) VALUES ('10'::my_uint);

Is there a way to avoid the single quotes?