OpenNLO Name Finder Custom Feature Generation

[Amir Pouya Agha Sadeghi]

Hello Guys, I'm new to OpenNLP. I'm currently developing Persian NER with
it , but unfortunately my recall is to low  and I decided to work with the
custom feature generator. I need to add some feature like word suffix and
work prefix or pass the word POS tag to it. I can not find any
understandable manual for it and because of that I'm literally lost.  Can
any one help me?