How can I add custom combo( select) in catalog plugin of item form ?
The combo which I want to add is static

In downloaded catalog plugin archive you will find two example files. One of them will describe how to add new fields to item form. That example adds checkbox. But you can add any type and count of fields in the same way: http://www.impresspages.org/docs/workin ... eld-types/ or even create your custom field type http://www.impresspages.org/docs/workin ... ield-type/