YOu need to add following three properties
1. Implementation Name : it should be same as model name
2. Implementation Type : It should be PSpice model
3. PSPice Template: This is most critical and bit complicated. For this I would recommend you copy this property from equivalent part from existing PSpice library. Or you should use PSpice Model Editor, generate Symbol for your model. This symbol would be rectangle shape (assuming your model is subckt type). Copy PSpice Template property from that(generated by Model Ed) symbol to your symbol. You need to convert pin name as per your symbol in PSpice template property.
Hope this helps.