Open external URL from menu

Hello…
i need open a file in a external site, from menu.
The filename is variable…
a) I can set a url from a variable, in link field, in menu?
b) I try to set a link to blank, and in blank set the link to the file, but not open…
Some sample, or help?
Thanks!!!

Solved:…
In the blank, in execute…

$AuxLink = ‘https://www.myurl.com’.[parameters];
$AuxLink = ’’;
echo $AuxLink;

If this is only to open an external URL from a menu it seems a bit convoluted.
You can use variables and the sc_redir macro in the onExecute event of a menu, thus ignoring the link set in the menu item (if there you cannot use variables)