Facility Control

There are 2 mechanisms you can use for this.
If your toggle button is a parameter, you can use params.setAccess(OID, 0) to disable the parameter and params.setAccess(OID, 1); to enable access.
If you are using a non-parameter button, you can enable/disable with ogscript.setEnabled(ID, true/false);

Here is a panel that demonstrates both techniques:

<abs contexttype="opengear" style="">
   <meta>
      <params>
         <param access="1" constrainttype="INT_CHOICE" name="Toggle Button" oid="Toggle_Button" precision="0" type="INT32" value="0" widget="toggle">
            <constraint key="0">Off</constraint>
            <constraint key="1">On</constraint>
         </param>
      </params>
   </meta>
   <param expand="true" height="104" left="22" oid="Toggle_Button" style="style:toggleButton" top="38" width="238"/>
   <simplegrid height="56" left="20" rows="1" top="160" width="243">
      <button buttontype="push" name="Disable">
         <task tasktype="ogscript">params.setAccess('Toggle_Button', 0);</task>
      </button>
      <button buttontype="push" name="Enable">
         <task tasktype="ogscript">params.setAccess('Toggle_Button', 1);</task>
      </button>
   </simplegrid>
   <button buttontype="push" height="73" id="dis-button" left="31" name="Disable Me For 3" top="281" width="243">
      <task tasktype="ogscript">ogscript.setEnabled('dis-button', false);
ogscript.asyncExec(function()
{
   ogscript.setEnabled('dis-button', true);   
}, 3000);</task>
   </button>
</abs>

Found this post, and it was exactly what I was after.
Question though, can you set a button as disabled by default?

<abs contexttype="opengear" style="">   <meta>      <params>         <param access="1" constrainttype="INT_CHOICE" name="Toggle Button" oid="Toggle_Button" precision="0" type="INT32" value="0" widget="toggle">            <constraint key="0">Off</constraint>            <constraint key="1">On</constraint>         </param>      </params>   </meta>   <param expand="true" height="104" left="22" oid="Toggle_Button" style="style:toggleButton" top="38" width="238"/>   <simplegrid height="56" left="20" rows="1" top="160" width="243">      <button buttontype="push" name="Disable">         <task tasktype="ogscript">params.setAccess('Toggle_Button', 0);</task>      </button>      <button buttontype="push" name="Enable">         <task tasktype="ogscript">params.setAccess('Toggle_Button', 1);</task>      </button>   </simplegrid>   <button buttontype="push" height="73" id="dis-button" left="31" name="Disable Me For 3" top="281" width="243">      <task tasktype="ogscript">ogscript.setEnabled('dis-button', false);ogscript.asyncExec(function(){   ogscript.setEnabled('dis-button', true);   }, 3000);</task>   </button></abs>