Field from BIRT not displaying

Hi,
I have a BIRT report, which is working in BIRT ok.
But when I executing this report in Reportserver, field is not outputting value - it is empty.

In BIRT the outputting chain for my field is: 1)Data Set → 2)Parameter-> 3)Field:

DataSet called “Product_type” used in this parameter consisting from simple mysql query:
select
ib_product_types.id,
ib_product_types.alias_name
from ib_product_types

Parameter’s “Product_type” properties are:
Data Set: Product_type
Select value column : id
Select display name : alias_name

Reqiured field is outputting the value from parameter called “Product_type”:
Expression used in this field: reportContext.getParameterDisplayText(“Product_type”)

So, in Birt my field outputing alias_name, but in Reportserver ouputing nothing…

Could somebody help, and explain what additional actions do I need to accomplish to output correctly field value in Reportserver ?
Thanks in advance.

P.S. Reportserver version 2.1