Check for null value for any Component Misc. Rate field in RTF/WFC statement template?

Summary:

Trying to check for null value in my compensation statement RTF template but getting 'failed to load' when I try to generate my statement.

Content (required):

We have a group of employees that we will load a value in the COMP_1_MISCELLANEOUS_RATE_3. For the rest of the employees we will not load any value in this field. In our statement I need to show a section if this value is> 0. But I need to show a different section if the employee does not have a value in this field. I would think that would be Null. I've tried using <?when: COMP_1_MISCELLANEOUS_RATE_3 = “”?> but that does not seem to work. I really don't want to have to mass load a 0 for all employees that do not