Larry,
You might want to search through the Brother category in this forum over the past week for a post where others were talking about colors. There is a PDF that talks about getting the color management set up correctly in Corel. Not sure if you are using Corel or something else. But you need to have this set correctly before doing anything else.
Then you are going to want to print a color chart out on the gold shirt. This will tell you the colors that are achievable for the color management settings you have in your software program and the heat press settings you use for curing the ink on that specific color shirt. If the color blue shows up you want, then you can use those specific RGB color settings to print the color you want. If not, you can try printing from a different graphic software program. The colors from Corel are different than what comes out of Photoshop. It has to do with the way a program processes color. The same thread I mentioned above had some color charts you can use. Otherwise, you can download different ones here -
CMYK & RGB Color Charts - MultiRIP Sublimation, Transfers, Photograph and Direct-to-Garment Printing RIP Softwares.
If you go through all the steps above and you are not able to get the desired color blue, then it could be a result of the color of the fabric altering the color of the transparent inks. Then your options are to use a different color shirt or to find someone that can print on dark garments so the white underbase will block out the color of the shirt.
Hope this helps,
Mark