How to use stored procedures with linked tables

In MySQL I have the following table:

CREATE TABLE `info` (
   `created` int(11)
);

And it is linked (via JDBC SQL Gateway) to Cache table mysql.info.  `created` field stores unix timestamp. So when I execute  this SQL in SMP:

SELECT created FROM mysql.info

I receive the following output (which is expected):

But I want to to display `created` field converted to ODBC timestamp format. To do that I call this SQL procedure

Class mysql.utils [ Abstract ]
{
/// Unix timestamp to ODBC
ClassMethod uto(unixstamp As %Integer) As %TimeStamp [ SqlName = uto, SqlProc ]
{
    set startday = $zdh("1970-01-01 00:00:00",3)
    set endday = (unixstamp \ (60 * 60 * 24))
    set endtime = (unixstamp # (60 * 60 * 24))
    set totalday = endday + startday
    quit $zdt(totalday _ "," _ endtime, 3)
}
}

But if I execute this SELECT:

SELECT created, mysql.uto(created) As "ODBC" FROM mysql.info

I receive the following output:

Instead of the expected output:

Then, I tried to use MySQL conversion function from_unixtime for the same purpose:

SELECT created, from_unixtime(created) As "ODBC" FROM mysql.info

However, I receive the following error message:

User defined SQL function 'SQLUSER.FROM_UNIXTIME' does not exist

Which is true enough I suppose.

But a question is, how do I apply stored procedure to a linked table field?