Solution : https://service.sap.com/sap/support/notes/1258173 (SAP Service marketplace login required)
Key words : 
zip /data/51001815 andjar -xvf 51001815_2, prepare prepare onldoc readme, zip usingjar -xvf 51001815_1, zip file format, download server logically, short text dvd, separate small parts, zip /data/51001815, small parts, download media
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