Here's how I assigned a value to the string variable:
${_EscapeTool.hash}set(${_EscapeTool.dollar}mystring = 'James "Jamie" Arthur Johnson')Here's what broke (Why?):
<img id="me" src="https://d13pix9kaak6wt.cloudfront.net/avatar/users/j/a/m/jamie.johnson_1374064104_11.jpg" alt="Picture of ${_EscapeTool.dollar}{mystring}" /><br />${_EscapeTool.dollar}mystringHere's what I did to fix it:
<img id="me" src="https://d13pix9kaak6wt.cloudfront.net/avatar/users/j/a/m/jamie.johnson_1374064104_11.jpg" alt="Picture of ${_EscapeTool.dollar}{_EscapeTool.xml(${_EscapeTool.dollar}mystring)}" /><br />${_EscapeTool.dollar}mystring