This is a very simple process.
The user must delete the Gmail COD files for gmail account using BBSAK.
If you are not familiar with BBSAK it can be a bit intimidating, I can assure you I had 0 knowledge of BBSAK (when I 1st attempted this), but it took all of 5 minutes and when very smoothly.
Here is the process:
1- Read the COD files using BBSAK
2- Sort by name to find the files quicker
3- Save the following files in case you want them in the future:
net_rim_bb_gmail.cod
net_rim_bb_gmail_resource.cod
net_rim_bb_gmail_help.cod
4- Then Delete the following files:
net_rim_bb_gmail.cod
net_rim_bb_gmail_resource.cod
net_rim_bb_gmail_help.cod
5- Do a battery pull
This will allow the email icons in the theme to be used, not the gmail icoms.