Could the setter be omitted in JSF - jsf-2

Question

I'm using WildFly 8.0.2 along with primefaces 5.2, i have a p:datatable, with a column that have a p:inputSwitch, the value on this p:inputSwitch is a method (that return either true or false), so it does not have a setter method, i have attached a p:ajax to handle the switching event (on/off), but when i change the value it always raise an javax.el.PropertyNotWritableException: Illegal Syntax for Set Operation exception (cause the value is a method ... and has no setter).
here is my code:
<p:column styleClass="status #{employee.haveSkill(skill) == true ? 'have' : 'dosntHave'}">
<div style="text-align: center;">
<p:inputSwitch value="#{employee.haveSkill(skill)}" onLabel="#{msgs.yes}" offLabel="#{msgs.no}">
<p:ajax listener="#{skillsController.addSkill(employee, skill)}" />
</p:inputSwitch>
</div>
</p:column>
i have tried with a c:set, that stores the result of the method in a variable and then assign it to the p:inputSwitch component, but that didnt work for me, and the p:inputSwitch is always set to false (although the EL expression for the style class of the cell is working fine), here is the code that i have tried:
<p:column styleClass="status #{employee.haveSkill(skill) == true ? 'have' : 'dosntHave'}">
<div style="text-align: center;">
<c:set var="have" value="#{employee.haveSkill(skill)}" scope="request" />
<p:inputSwitch value="#{have}" onLabel="#{msgs.yes}" offLabel="#{msgs.no}">
<p:ajax listener="#{skillsController.addSkill(employee, skill)}" >
</p:ajax>
</p:inputSwitch>
</div>
</p:column>
So is there like a way to tell jsf or el not to fire the "set" method for that component? and just execute that listener on the ajax??
UPDATE:
I have also tried with the ui:param, but it also raises the javax.el.PropertyNotWritableException :
<p:column styleClass="status #{employee.haveSkill(skill) == true ? 'have' : 'dosntHave'}">
<div style="text-align: center;">
<ui:param name="have" value="#{employee.haveSkill(skill)}" />
<p:inputSwitch value="#{have}" onLabel="#{msgs.yes}" offLabel="#{msgs.no}">
<p:ajax listener="#{skillsController.addSkill(employee, skill)}" >
</p:ajax>
</p:inputSwitch>
</div>
</p:column>