jQuery Grid Plugin - jqGrid

Hello,

Short version of the question:

I need to build a jqgrid step-by-step, by adding or changing some options at a time, and then render the grid when I've finished the work with the options.
Is it possibile? How may I achieve this?

Long version of the question:

I've written a generic base class in php, which creates a jqgrid command with some options.
This base class contains the basic methods for building the grid and creating a skeleton jqgrid command.

Then, I have some other classes which extend the base class and should modify the existing options or add new options to the basic jqgrid, such as edit buttons and so on.

I'm looking for a simple way to do that, without having to remap the options in php.

Is there a way to create an instance either of jqgrid or of the options object and then modify it before rendering the grid?

Thank you

Regards