Set interpeter for RPM hook scripts explicitly

[vyablokov]

I'm building an RPM package and I would like to know, how can I set bash interpreter explicitly for prein, postin, preun and postun scriptlets. I'm trying to do this because I would like to be sure that Bash shell is used to run this scriptlets during installation (but default interpreter is /bin/sh as I can see). If I understand correctly, when RPM SPEC file is being written manually, there is an ability to set interpreter using -p option, e.g.: %pre -p bash So is there is any way to specify interpreter using ospackage RPM plugin capabilities?