WotLK Transmog leather to plate - need info

[hustlahbrodz]

Hello guys! So i got Mok'Nathal Beast-Mask and I really want to transmog my Relentless plate helm to it but game won't let me. I think this shouldn't be the way it is as I'm allowed to wear leather armor anyways. Now, I remember I used to see a lot of people back in cata realm transmoging swords into axes and such. I think they used a macro or something. Could you tell me whether this will work on Icecrown and how it needs to be done exactly. Also, is this banable?

Thank you!

[Skuddy]

plate to plate leather to leather etc. bypassing that would likely count as bug abuse/ an exploit and result in a ban.

[hustlahbrodz]

It's not like you're using a 3d party program or anything ... and people used to do it a lot. That's why I'm actually asking. I don't think this could get you banned back then.