Modelsim, analog format of float64

I have made a simple project using floating point. But when i tryed to simulate it in modelsim, i couldn't see floating point signal in analog format. It looked like Modelsim used floating point signals as integer. There are two signals on the screenshot "y_1" - floating point signal and "y" its fixed point represantation. How can I make Modelsim to build analog graphic using floating point?