Concatinating String Values From Multiple Rows

I currently have some SQL code that is used to build a string that is a concatination of string values across multiple rows.  The subqueries in the script sometimes return NULL values so I use the following statement to change the default behavior of the concatination operator which prevents my query from returning NULL:

SET CONCAT_NULL_YIELDS_NULL ON

Here's the code snippet:

select DISTINCT

(SELECT CASE WHEN (t1.MaskValue & HDR.TranTypeID)=1 THEN ' ' + t1.description ELSE '' END FROM transactiontypes t1 WHERE (t1.MaskValue & HDR.TranTypeID)=1) +

(SELECT CASE WHEN (t2.MaskValue & HDR.TranTypeID)=2 THEN ' ' + t2.description ELSE '' END FROM transactiontypes t2 WHERE (t2.MaskValue & HDR.TranTypeID)=2) +

(SELECT CASE WHEN (t3.MaskValue & HDR.TranTypeID)=4 THEN ' ' + t3.description ELSE '' END FROM transactiontypes t3 WHERE (t3.MaskValue & HDR.TranTypeID)=4) +

(SELECT CASE WHEN (t4.MaskValue & HDR.TranTypeID)=8 THEN ' ' + t4.description ELSE '' END FROM transactiontypes t4 WHERE (t4.MaskValue & HDR.TranTypeID)=8) +

(SELECT CASE WHEN (t5.MaskValue & HDR.TranTypeID)=16 THEN ' ' + t5.description ELSE '' END FROM transactiontypes t5 WHERE (t5.MaskValue & HDR.TranTypeID)=16)) as 'Transaction Type'

FROM HDResponse HDR

Here's the underlying table structure:
CREATE TABLE [dbo].[TransactionTypes](
             [ID] [int] IDENTITY(1,1) NOT NULL,
             [Description] [varchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,        [MaskValue] [int] NOT NULL) ON [PRIMARY]
CREATE TABLE [dbo].[HDResponse](
             [ResponseID] [int] IDENTITY(1,1) NOT NULL,
             [LoggedDateTime] [datetime] NULL,
             [ResponseTypeTripID] [int] NULL,
             [ResponseTypeID] [int] NULL,
             [ResponseTypeObjectID] [int] NULL,
             [ObjectID] [int] NULL,
             [IDHolderID] [int] NULL,
             [TransportCode] [int] NULL,
             [CardID] [int] NULL,
             [IssueCode] [smallint] NULL,
             [EventDateTime] [datetime] NULL,
             [Response] [bit] NULL,
             [TranTypeID] [int] NULL)
             ON [PRIMARY]

The problem I am having is I need to be able to use the query above in a view used for reporting.  Unfortunately, you cannot use SET CONCAT_NULL_YIELDS_NULL ON in a view.  This causes my query to return NULL if any of the subqueries return NULL.  I could create a function to do something similar and reference the function in the query but I can't help but think there must be a way to get this done in a single query.

Any thoughts or ideas would be greatly appreciated.

Thanks!!!!!