Using Xp_cmdshell In A Trigger

I'm using xp_cmdshell to output a text file from a trigger like this

CREATE TRIGGER [CreateFile] ON tblApplications
FOR INSERT
AS

DECLARE @FirstName varchar(75)
DECLARE @LastName varchar(75)

Declare @strcmdshell varchar(150)
Declare @filename varchar(100)
Declare @filecontents varchar(150)

SELECT @FirstName = FirstName FROM INSERTED
SELECT @LastName = LastName FROM INSERTED
SELECT @filecontents = 'FirstName: ' + @FirstName+char(13)+'LastName: ' +
@LastName+char(13)+
SELECT @filename = 'c: est.txt'
SELECT @strcmdshell = 'echo '+ @filecontents+ ' >'+ @filename
exec master..xp_cmdshell @strcmdshell

When I concatenate @FirstName and @LastName(neither is NULL) and try to
insert a blank line with char(13) the command doesn't run. If I don't use
char(13) it works fine. Does this make sense? IS there any other way I can
format the output file.

Thanks