Multi-Texturing Issues

[goro]

We are experimenting with Vizard 4 Trial Version. We are implementing Advanced Shaders. While Implementing them we are facing problems. For shaders we need to map multiple textures & cubemaps over the object. Vizard only permits 4 textures/Cubemaps. We can apply those textures on units (layers) 0, 1,2 & 3; but not on units 4,5,6 etc. Are these issues because of trial version? If Vizard only permits 4 textures then how to apply more than 4 textures?