Where is setting of mouse middle button to use as pan in Auto-CAD 2013 & what is change required to use mouse middle button as pan ?

AUTHOR: Mayur Navasare
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IP: 106.78.221.60
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[1_Name] => Mayur Navasare
[2_Email] => navasaremayur@gmail.com
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[4_Comment] => Where is setting of mouse middle button to use as pan in Auto-CAD 2013 & what is change required to use mouse middle button as pan ?
)