The standard Amino AmiNET remote controls are universal, capable of controlling the basic functions of the television as well as the Amino Set-Top-Box (subject to the TV brand code being pre-programmed in the remote)

Amino AmiNET remote controls

The remote control operates in one of two modes, either STB mode or TV mode. The mode is selected by pressing the TV or STB mode-select button at the top of the remote. When pressed, the TV or STB mode–select buttons illuminate briefly to indicate that the mode has been set. When any function button on the remote is pressed, the TV or STB button will light to indicate that a command is being transmitted in that mode. If a button has no valid function in that mode, neither the TV nor STB mode buttons will light.

In order for the remote to transmit the correct signals to control the TV, the remote must be programmed with a code corresponding to the type of TV in use.  Available codes are listed in the user guides - see TV Brand Codes.

It is not possible to disable the TV button on the remote so that the remote is always in STB mode, as the TV button cannot be reprogrammed with an alternative function. 

Also, as its default function is not handled by the STB, it cannot be 'masked out' in your application.  See Amino Remote Controls - disable TV button or TV mode