Cannot use parameter on Postgres Query

Hi,

we created a report accessing a Postgres database. It runs without problems providing the expected info.

The problem arises when we try to add a parameter in the select statement. No matter what we do we get a "[42703] ERROR: column "MyParam_P" does not exist."

The query syntax simplified:

select Fielda,Fieldb,@MyParam_P as param from MyTable

A Report parameter has been defined as @MyParam

A Dataset parameter has been defined with Name=MyParam_P and Value=[@MyParam]

We tried every syntax we could imagine (brackets, using @ or not, ...) with no success.

Filtering the rows with an expression (i.e. Fielda=@MyParam) works as expected but this is extremely uneficient and doesn't solve the real problem.

Any idea what are we doing wrong'

Thanks