You have already asked this directly to moderator CKPT who is discussing it in the moderator forum with other moderators and the administrators.
For the time being:
Documents in spaces are restricted to certain individuals such as the content managers of those spaces, so they cannot be populated by just any member of the community.
This is partly due to the need to ensure the quality and quantity of what content is posted, but is also a restriction placed due to abuse by spammers in the past.
So, in short, you cannot put your documents into the document content of a particular space, you can only create them in your profile.
The documents you have linked to show "unauthorized" when trying to access them, so I assume you have limited who can see them, or they are still in draft.
If the admin can review your documents and deem they are appropriate to be put into the content of that space, they will no doubt contact you when such a decision has been made. At the moment though, you'll have to wait until the admin are available to discuss this.
Thanks for the update
I am the Community Manager for the Database space.
We do have an official article submission process which involves a article review cycle.
You can send the article to me in email and I'll work with you to publish the article.
In the meantime, check out this recent article on the topic:
Hello LKR I really appreciate your response. Would you please send me your email address. I want to submit my article for review cycle. Regards Hitgon
Thanks you very much
I just send my articles on your id.
Also, if you can set permissions for the linked whitepaper in your Ideas space to be public, we can all open it...right now it shows as "unauthorized access."
Sorry for difficulty...we'll get better at this I promise.
Thanks you very much for consider it to be Publish.
Please find the attached whitepaper.