SQLColAttributes and SQL_DESC_NULLABLE

Hello,
I'm using .Net Odbc Data Provider, ODBC driver 8.1.x and PostgreSQL 8.1.0.
To find out whether column can be null, the .NET calls ODBC function 
SQLColAttributes. Problem is, that this function allways returns  
SQL_NULLABLE, even for columns declared as NOT NULL. I tried to enable 
"Parse Statements" option of the driver, but it didn't help.
I downloaded the latest sources, compiled them to see what's going on 
inside and found this:
It seems that for SQLColAttributes to return something else than 
SQL_NULLABLE, "Parse Statements" option MUST be turned on. Am i right?
For some reason stmt->manual_result  is true, which causes that the 
statement is not parsed. What does this stmt->manual_result  mean?

Thanks in advance.

Robert Jires