So where do I begin....

I need any advice that I can get please...

My partner has been living with my in NZ now since 2012. He original come over on a visitors visa and this application was completed by his father as my partners English at the time was very poor. This was approved for 3months then he extended his visa for another month and this application was completed by his sister again my partners English was not very good...My partner trusted that the form would be correct and just signed. We started applying for partnership visa and I have always completed all his forms and I have made sure I have declared that I helped on all forms. So my partner has a criminal record from his home country back in 2008 that he pleaded not guilty to till 2011 after finally giving up as he wanted to move on with his life. He could not afford a lawyer so and the oppositions lawyer advised him to plead guilty as this would be his first offence he would be ok. So this is what he did. Below is what shows on the police record:

1 - Riotous Assembly
2 - Destruction of building by rioters

Sentence:
18 months imprisonment
12 months imprisonment
12 months imprisonment
The sentences made concurrently sentences suspended in total for 2 years on the condition the accused complete the life skills program offered by Salvation Army and also carry out 110hrs community service.

So he never spent any time in prison and he completed his salvation army course and 110hrs community service.

Since I we have been applying under partnership category I have always declared that he has a criminal record and also explained the situation wit every application. We did not submit a copy of police record until the 3rd application which was to extend his work visa. However the case worker that received this application found evidence in our application to approve a character waiver and that the application that the visitor visa application mistakes were just that MISTAKES. We were then told that the next application will need to be a residence visa so we put in a residence visa which came back declined as he was not of good character and that he did not declare his convictions in visitor visa application which we know is true but we explained this in and the case manager in previous application accepted this and approved it.

We are now going to apply for a special direction. So I need to know what evidence I should make sure I submit to have a better chance of getting approved??? He is a good man and apart from the conviction in 2008 he has never been in any other trouble. He is a good step father to my son for the past 4years. Since he has had a work visa he worked and he is committed to mea

Any ideas or advice will be much appreciated.

Thanks