Attach handrail to vinyl siding w/o crushing siding

I need to attach a small 3' handrail to vinyl siding. There are two square 4" metal brackets for attaching the railing to the house. The railing is simply a long aluminum tube.

I plan to attach the brackets to studs under the siding, but how do I attach it without crushing the siding? I can imagine several possible ways to do it but have been unable to find a recommended way.

Thank you in advance.