You cannot modify a document through the plugin.
To amend one, you need to use the Qlikview client - the good news is that with v9 there is the concept of leased licencing where a user has a named CAL at the server. You would need to install the client to the individual user machine, tell it where it should lease the licence from (see under User Preferences - ctrl&alt&u under the locations tab) and then enable the user to be able to see the folder on the server where the documents are stored. Opening the document with the client then allows the user to modify the document and save it back. Oh, and the server should be set to allow licence leasing (QMC>Licences>CALs).
Other than that, you would have to give access to the server to the user who could use remote desktop connection to use the QV client installed there but I think this would be less preferable.
Controlling multiple accesses might be an issue though if you have several people amending the same document.
Hope this helps,
The feature you're referring to is called "collaboration". It states on page 219 of the QlikView Server manual that collaboration is disabled for SBE. You indeed would need EE to allow end users to create their own objects.
Another thing to note - collaboration doesn't allow users to actually modify the source application. All it does is "overlay" user created charts onto the application sheets. These objects can be private, or the user can share them with other users. You definitely can't change the load script or reload with collaboration. Collaboration allows users to create charts, bookmarks, and reports.
There is a way in section access to define the type 'Users' to users that you the then limit certain things like accessing the script window. The users type 'Admin' modify what the 'Users' can do or cannot do in Document Properties->Security.
It might be easier to create a QV file with just the script and then another QV file with charts that load the other QV file with a binary load. You only give the user access to the QV file with charts and although the user can enter into the script window, there is only one line of script to load the script from another QV file.