SAP's wide support for long texts is not reserved for SAP programs only. If you are planning to store long texts with your tables, you should do this exactly the same way SAP does... By using the ID, Language, Object and Name, you can identify your own texts and incorporate them in SAP's textpool. The ID can probably be reused from one of SAP's ID's. Use LTXT for example. The Object should be created (as new), just to ensure you are not mixing up any other texts (and thus other applications).
The other thing you have to keep in mind is the data modelling part, if you want your text to link up to a certain object e.g. a material, then you should use the fieldTDNAME the text name, to link it to that field. Thus the value of your TDNAME could be011000000000000201223, which is "Material 201223 in client 011". Actually, client can be omitted since texts from the text pool are client dependant.