Axis title concatenation issue

Hi,

I wanted to make the Axis Title of a chart equal to a parameter value concatenated with " in Thousands".
The possible parameter values are "Units" and "Amount", obviously strings, but when I try to create the expression

=Parameters!Unit_or_Amount.Value + " in Thousands"
or
=Parameters!Unit_or_Amount.Value & " in Thousands"

SSRS underlines everything after Value in red, i.e. it didn't want to concatenate them as is.
Do I have to do a
=CSTR(Parameters!Unit_orAmount.Value) + " in Thousands"
or
=CSTR(Parameters!Unit_orAmount.Value) + CSTR(" in Thousands")?
Doesn't SSRS know they're strings?

Thanks,
Jnana

Jnana Sivananda