Hitch retrofit

[Dougray]

Orbit can flash ECUs but not all the ECUs are tested and validated.  The hard part finding the correct SBL and Data and Exe vbf files.   Drop an email to support maybe they can help you. 

But if they cannot you still have a solution. 
Here is the installation instructions for XC60 T5.  The SW part number you need is 30644823 and it's around $40. If you are living in US, you can get VIDA subscription and install the software yourself.  It should detect and give you correct software in the HW changes TAB.  
If you are not living in US, just visit the VOLVO service, they should be able install the software since it is an optional official accessory. 
Just remember to revert back to original settings before either of the two options above.  If you do the official way you do not need to disconnect the ECU every time you visit the service.  If you don't disconnect the module and just revert back the changes to original,  you might ran into issue (blocking the car) with the Volvo service depending on the VOLVO policies in the country you are living in because VIDA will report the new module you installed.

Hi IMAY, the TRM is one of the modules which has been tested and can be flashed using Orbit. I'm not in the US, so can't pay for VIDA access (and would prefer not to anyway). 
I must extend my thanks to Power6 for the assistance when contacting support. My new module is now flashed with the correct software via the Orbit ECU tools and is working perfectly with the configuration settings enabled. It was a very simple process. Very impressed by the support for Orbit, it's an excellent tool! 
Having paid £80 for a used, genuine retractable towbar, button and mount through a contact who works at a Volvo dealership and another £110 for the module, plus £50 for him to install (I could have done it, but he took 30-40 min and would prob take me a few hours), I'm absolutely delighted!
Incidentally if you already have the double button for seat release or air suspension, you can cannibalise a single towbar button and fit it into the blank space of your original. It was easier to find a used single towbar button for me.