Adding space service is adding disk storage to your capacity in use.
This service is based on requesting.
After the requesting, you are became to Fee User(ePublishing), then you can use a lot of additional functionalities.
Also you can use the value added services.
Adding Storage Price 1GB : 1,000US$(1Month)    
   Enterprise User's Services and functionalities
Services and functionalities Free User ePublishing User eAuthoring User eCommerce User
Download Published Title Not Allow Allow Allow Allow
Number pages per Published Title 50 pages 300 pages
Max Size per Published Title less than 40MB less than 200MB less than 500MB No Limit
Max Size per page less than 10MB less than 20MB less than 30MB less than 50MB
Document(PDF,Word,PPT) File Extracting Support Support Support Support
AD Page Insertion AD page insert None None None
Published Title Logo Change Not support Support Support Support
Published Title Page Add/Delete/Replace Not support Support Support Support
Index Support Support Support Support
Cliping from Animation file Support Support Support Support
Image extraction from Published Title Not support Support
HTML Link of Published Title Limited Full Full Full
Multiple PDF Server uploading Impossible Impossible Possible Possible
Animation Authoring Impossible Possible Possible Possible
Editing Default1.html Not support Not support Support
Shopping Mall None None Support Support
My Skin None None Support Support
Imbedded Javascript None None Support Support
Active DBook None None Support Support
Android/IOS App Packing None None Support Support
Slide Show None None Support Support
DBook Replace None None Support Support
Customized Input/Creation None None None Support
Auto. Server Copy None None None Support
Photo Studio None None None Support
HTML5 Editor None None None Support
ePUB Extraction and Edit None None None Support
SOAXML Extraction None None None Support