Powerbuilder an Chinese Characters

I am using powerbuilder 12.5.2 Build 5006 with a MSSQL Server 2008 SP2 database.Version 10.0.5500.0

The connection to the database uses ODBC and the connect string is

DBParm=ConnectString='DSN=StarKISHK_Dev;UID=;PWD=;APP=%app%;WSID=%wsid%',ConnectOption='SQL_INTEGRATED_SECURITY,SQL_IS_ON',PBCatalogOwner='dbo',StripParmNames='Yes',DisableBind=1

I can retreive and display Chinese characters, however if I enter Chinese characters in a datawindow, and perform an update, only question marks are saved to the database. The update uses a stored procedure.

The datawindow column is called stock_message and is defined as a string, the parameters for the stored procedure are

[usp_update_day_stock_message]

    @shop_no            SMALLINT,

    @trading_date        DATETIME,

    @stock_message        NVARCHAR(MAX)

and the table is defined as

[dbo].[trading_conditions](

    [shop_no] [smallint] NOT NULL,

    [trading_date] [datetime] NOT NULL,

    [stock_message] [nvarchar](max) NULL

What is preventing the Chinese characters being saved properly?

(I saw an old post saying set disablebind=0 in the connection string but that didn't work)