Hello Sergej,
In order to answer your question, I read thru your paper and by the content I understand your research is focused on analytics on twitter data not on building technical infrastructure around integrating and analyzing twitter data. If that is the case, it really boils down to time vs. money., you can definitely spend some money to get a ready made solution form market and save on time if financial resources for the project permit else you need to spend time to build the integration to save on money component. I am not aware of any plug & play product available that will work with little to no customization/development effort. Text analytics on HANA is fairly powerful especially and I believe it should get the job done.
Just a thought from my side., since you are in academic setting, why don't you involve resources from department of computer sciences to contribute to your research in the way of building infrastructure around integrating twitter data to HANA and it would be of great benefit to the students who work on it. This would be a great collaboration.
Regards,
Gopal