MIME Charset (iso-8859-1) Question

[mubx2000]

I Did Some Application (In Symbian C++) To Get Email Message from POP3 Server Using Sockets Engine, The Message Containes (Arabic) Language Text ,Inside the message body It's Charset should be (iso-8859-6) , When I recived the email message I found that the recived charset is (iso-8859-1) which is the Charset for english language Here Is The compleate message (Subject+body):

 //////////////////////////////////////////// 
Subject:=?UNKNOWN?B?49Hd3sfK?=
 
 
--Boundary_(ID_ggpCVFXalUKpTet73vw7Ng)
Content-type: text/plain; charset=iso-8859-1
Content-transfer-encoding: 8BIT
 
Representation Of Writing
ÊãËíá ÇáßÊÇÈÉ
*
 
---------------------------------
Do you Yahoo!?
Get on board. You're invited to try the new Yahoo! Mail.
 
--Boundary_(ID_ggpCVFXalUKpTet73vw7Ng)
Content-type: text/html; charset=iso-8859-1
Content-transfer-encoding: 8BIT
 
<div>Representation Of Writing</div> <div>ÊãËíá ÇáßÊÇÈÉ</div><p> 
<hr size=1>Do you Yahoo!?<br> 
Get on board. <a href="http://us.rd.yahoo.com/evt=40791/*http://advision.webevents.yahoo.com/mailbeta">You're invited</a> to try the new Yahoo! Mail.
 
--Boundary_(ID_ggpCVFXalUKpTet73vw7Ng)--
///////////////////////////////////////////////////////////
 

As you see from the above lines The Subject = (=?UNKNOWN?B?49Hd3sfK?=) and the Charset for the arabic letters is (iso-8859-1) , Can Any Body Tell Me How The Charset Comes For english language althogh that the actual text Is arabic?

Why The Arabic Text Displayed With (Non-Understandable) Characters Although that the (PC) supporting arabic langauge? How We Can solve this Problem By Decoding Into (8-Bit) Decoding?What Does (UNKNOWN) on the subject field means?

MY HandSet Is NOKIA (6630) And It Is Arabic Enabled HS.