How to use SQL functions with parameters?

Dear all,
I need to filter a query using an SQL function.

In SQL this would be achieved with the following statement:
    select * from myTable where key in (select * from myFunc(myParam))

I tried the same with ODB-ODBC, and this worked using the following query
string:
    String oqlQuery = "select myObject from " + myClass.getName() +
        " where key IN (select * from myFunc(" + myParam.toString() + "))";

However it generated an error at the moment of binding the parameter using
the following query string:
    String oqlQuery = "select myObject from " + myClass.getName() +
        " where key IN (select * from myFunc($1))";

After creating the qury with:
      query.create(oqlQuery);

The error (QueryParameterCountInvalidException) was generated at the
following line:
      query.bind((Float)myParam);

Can anybody tell me if it is possible to use the query string in the
second form?

Thank you,
Francesco.