Bound parameter is not substituted

Hello all,

I am trying to create a stored function through ODBC connection,
But the parameter marker inside the function is not substituted.
In the following snippet, '?' is not substituted, and I got a syntax
error around it.
If I replace the '?' with '2', it is OK.
The psqlodbc I am using is 08.02.0400 together with unixODBC:2.2.12 on
OpenSUSE 10.3.
Is there a solution or workaround?

Thank you.

--------------
std::stringstream ss;
ss <<
"create or replace function plpgsql_setDocAttrs() returns
void as $$ "
"declare "
"pid integer; "
"begin "
"pid := ?; " // parameter marker
"end;"
"$$ language plpgsql volatile;"
"select plpgsql_setDocAttrs();";
// prepare statement handler
Stmt stmt();
// prepare the statement
stmt.prepare(ss.str());
stmt.bindNextParameter(
SQL_PARAM_INPUT,
SQL_C_LONG,
SQL_INTEGER,
0,
0,
&id,
0,
0);
stmt.execute();
---------------

ning