Change Ambiance toolbar colours

Hi there. I'm Rafael Laguna, member of the Lubuntu Artwork Team. This flavour uses a "copy" of the standard Radiance theme from Ubuntu. But now, Light themes has changed a lot, and we need to re-adapt again. Our problem is that we cannot change the toolbar gradient colours (still light brown). We are using these attibutes:

@define-color toolbar_base #e0e0e0;
@define-color toolbar_final #bcbcbc;
@define-color toolbar_border #fff;

but nothing changes on the toolbars. Obviously my knowledge of the syntax is very poor and sure it's my problem. Can you help me with this, please?

Thanks in advance.