convert string to Binary File

[fligant]

Hello all,

i want create MMS File ,
To Create mms file have to write some haders .
First one (X-Mms-Message-Type: m-send-req)

i write that string to file when i open that file i can just read that string as normal text "X-Mms-Message-Type: m-send-req"

but when i open other mms files its be like that

Œ€?1267008088 ?’‰?…K…—ê0 122555383/TYPE=PLMN –
êFW: Dodo „ ³‰application/smil

what i want is how i write that string "X-Mms-Message-Type: m-send-req" to file and when i open that file with notpad i fiend it like that

Œ€?1267008088 ?’‰?…K…—ê0 122555383/TYPE=PLMN –
êFW: Dodo „ ³‰application/smil


i use that code

FileStream stream = new FileStream("C:\\mysecretfile.mms", FileMode.Create); 
BinaryWriter w = new BinaryWriter(stream); 
w.Write("X-Mms-Message-Type: m-send-req"); 
w.Close();

thank you for your help .