Hi J Svete,
I also would suggest to use content-repository. It should not be hard to use it. Take a look at the file-storage package and see how it puts binary data and takes out binary data.
I can also email you about 3 files that uses the content-repository. In anycase it is encouraged to use the current underlying data model of OpenACS if possible. Once you are used to content-repository it takes only a couple of minutes to modify other packages to use it. You will also be inheriting some good features for content-repository such as versioning, attachment to parent content_items etc.
Of course being at a higher level may not give you knowledge on how things are really working.