Get access to all properties in Assembly BOM


I try to integration my application with Nav 2013 R2. I create my application in C#.

I published Assembly BOM as SOAP Web Service, but I can’t see all properties in my objects (Bom_Description, Installed_In_Line_No, Line_On and Parent_Item_No). I need Parent Item No. property, but I can’t see it.

Why I can see only part of filds in my Web Service ?