Move text without moving mask?

[avpromedia]

I created a text, a purple rectangle, and a mask.

The mask is on the text layer, the purple rectangle's position is pickwhipped to the text's position.

If I move the text with the selection tool, all 3 objects move.

If I change the anchor point x or y value of the text transform property, the text and the mask moves and the rectangle stays.

If I move the text with the pan behind tool, the text and the rectangle moves and the mask stays.

How do I move just the text, while the mask and the rectangle stay, either with a tool or by changing some number(s)?

I'm trying to create a text that scroll horizontally into the rectangle area. The mask will eventually be made same size and position as the rectangle.

[Mylenium]

Use a track matte, not a mask.

Mylenium