How to apply padding size on a GridLayout using CSS

Dear colleagues,

I am trying to figure out how to increase the padding size around some components that I have added on a GridLayout component in my application. I have finally suceed in finding the following CSS class which seems to be related to vaadin GridLayout component.

.v-gridlayout-spacing-on
{
padding-left: 10px;
padding-right: 10px;
padding-top: 10px;
padding-bottom: 10px;
}

This works fine, but here the problem comes.... I would like to apply this rule for a specific component in my application by using the setStyleName method.

Could anyone tell me what I must change on the above CSS and how I can call the setStyleName on my gridlayout component?

GridLayout grid = new GridLayout(3,3);

grid.setStyleName(XXXXXXX);

Thanks in advance
Leandro