Setting screen resolution

[Not2Smart]

I have installed UltraVNC 1.2.1.7 on a VM and connected with Viewer from another system. I am able to log in just fine. I am not able to set the resolution to anything higher than 1280x800. The client machine is at a resolution of 1900x1200. How can I increase the screen resolution of the VNC connection session to something higher than 1280x800?

[Not2Smart]

Perhaps this question isn't as straightforward as I thought it would be.

Can someone tell me what determines the maximum resolution in a VNC session? Is that a limit built into VNC? I cannot get it to go over 1280x800. Is that a hard limit in UltrVNC?