Modeling heat transfer involving a phase change (ice to water) using Abaqus

I'm modeling the transient heat transfer of a cooler with an ice pack in it. How does one accurately model the phase change of the water? Here's what I've tried so far:

 1. Added latent heat property to material card. Used Latent heat = 334 kJ/kg, Solidus Temp = 0, Liquidus Temp = 0

   Result: Error, Solidus and Liquidus temps cannot be equal

 2. Solidus temp = -0.01, Liquidus temp = 0.01

   Result: Analysis ran, but diverged very early in the analysis.

So I'm wondering if the issue is that my Solidus and Liquidus temps are too close together. After reading a little bit, it seems that the Latent Heat keyword might be designed for use with alloys and the like that have a large temperature range where they're in a multiphase state. As far as I know, water is not like this, and melts at 0 C (under normal conditions). Can someone help me figure out how to get this thing to converge, and let me know if I'm right about the behavior of water?

Thanks,

Marcus