What Statute Did I Violate?

Apparently that's a tough question for Salt Lake City to answer.

I've asked two times for the parking hearing officers at @slc.gov to show me the statute that states I need to display the temporary registration on my REAR window. This was the first thing they sent:

12.56.040: VEHICLES; REGISTRATION AND PLATES:Every vehicle at all times while being driven, stopped or parked upon the streets or alleys of this city, shall: a) be registered in the name of the owner thereof in accordance with the laws of the state, unless such vehicle is not required by the laws of Utah to be registered in this state; b) display in proper position two (2) valid, unexpired registration plates, one on the front and one on the rear of such vehicle; and c) when required, current validation or indicia of registration attached to the rear plate and in a manner complying with the laws of the state of Utah, and free from defacement, mutilation, grease and other obscuring matters, so as to be plainly visible and legible at all times. However, if such vehicle is not required to be registered in this state, and the indicia of registration issued by another state, territory, possession or district of the United States, or of a foreign country, substantially complies with the provisions hereof, such registration shall be considered as compliance with this code. (Ord. 48-86 § 1, 1986: Ord. 62-84 § 1, 1984: prior code § 28-3-177)

After I told them I don't see anything in that statute about a temporary registration or where to display it, they sent this:

41-1a-211.   Temporary permits -- Other laws applied.

            (1) (a) The division may grant a temporary permit to operate a vehicle for which:

            (i) application for registration has been made, or, in the case of a newly purchased vehicle, will be made;

            (ii) evidence of ownership is provided; and

            (iii) the proper fees have been paid.

            (b) The temporary permit allows the vehicle to be operated pending complete registration by displaying:

            (i) the temporary permit; or

            (ii) other evidence of the application under rules made by the commission.

            (2) If a vehicle is operated on a temporary permit issued under this section or Section 41-3-302, that vehicle is subject to all other statutes, rules, and regulations intended to control the use and operation of vehicles on the highways.

Again, there is no mention of where the permit must be displayed. When I pointed that out they replied, "On top of this section it says other laws apply." So, apparently, "other laws" are the ones I'm breaking. But they still can't tell me which other laws those are.

They have recommended that I get an attorney to advise me on the law, told me I can take this to court and said they will no longer reply to my emails.

I just want them to tell me the specific law I'm breaking. They contend I have broken a law and owe them $10. I want to know what is that law. Is that too much to ask?