[exim] lsearch with spaces

Hi,

I have tried to find matching x-mailer lines by using lsearch from a
text file, however since it often contains spaces it's never finding
anything :(. and i thought i ask if it's possible there is some option
or possible to change the lines in .txt so it can find anyway, i have
tried to put \ before spaces, and tried replacing spaces with ., but
that didn't work

condition=${lookup{$h_X-Mailer:}lsearch{/etc/exim4/current-xmailer.txt}{yes}{no}}