Are you still having this issue?
You can use Native's suggestion or you could install the LiteBans web panel in a subdirectory and have a customr redirect located in your navbar on your forum which works very well.
While you are all waiting for an update to the module which I am sure Samerton is working hard on, think about using the iframe feature of NamelessMC and embed your webstore (e.g Tebex) into a custom page.
If you are using the Chrome web-browser and iFrame elements are not displayed in your custom pages try the following tips.
1. Tick the 'Unsafe HTML' box in the custom page configuration
2. In the Chrome address bar click the shield and disable 'Block Unsafe Scripts'.
I hope this helps! :)