TCL error "bad option name" when doing ACCESS::session data set

Hi,

just a quick one: i got a variable that has some user-input, which i got to push into a session-variable (for access-policy processing). Now we got a case, where the content of the var starts with a "-", resulting in

bad option name (line 1)setting variable session.test for sid (null) fail
ed (line 1)Illegal argument (line 1) (line 1)     invoked from within "ACCESS::session data set session.test $myvar"    (iRule proc "/Common/RBUTIL::push_to_session") (line 15)
     invoked from within "call /Common/RBUTIL::push_to_session"

What i already tried is to

• give him the SID of the current session (this just removes the "null", but still the same error)

• escape the leading "-" with a backslash

• trying to terminate the options by using -- (does not work for access::session data set)

Is there any way to tell the underlying implementation that my session value is not to be interpreted as an option?

Thanks much in advance, Cheers, Rene