Execute PLSQL anonymous block with Hibernate

I need to run multiple function in Oracle with Hibernate

FUNCTION ISNUMBER(value IN VARCHAR)
    RETURN NUMBER DETERMINISTIC AS
RC NUMBER;
BEGIN
    IF (value IS NULL) THEN
        RETURN 0;
    END IF;
    RC := TO_NUMBER(value);
    RETURN 1;
EXCEPTION WHEN OTHERS THEN
    RETURN 0;
END;

But when running Hibernate it gives the following error: org.hibernate.QueryException: Space is not allowed after parameter prefix ':'

As expected Hibernate understands the character ':' being a parameter identifier for Query.

I read some articles saying that in String should put two backslashes, I ran with them but gave the same error

Can anyone help me? I use Hibernate 3.6