Well, VBM is SAPUI5 only and thus not available in OPENUI5.
First there is a license difference between those two. So can use VBM only if you are licensed to use SAPUI5 in your apk.
Second, unfortunately there is no current download of a SAPUI5 runtime zip like it is available for OPENUI5. You have to "rip" VBM from SAPUI5 and put that in your resources folder at the appropriate location.