Phil I am running 91085 and I see the browse button as Saranraj's
screenshot shows, I don't know why it doesn't appear for you.
That being said, the browse button only brings up a network
location view which lets you browse network computers to find an icon
file, it does not let you browse your computer locally to find an icon
file and have it uploaded to the configuration to be pushed to the
target computers.
What I've had to do was set up a configuration that copies an
ICO icon file to the target computer at say C:\Windows\customicons and
then wait for that to complete, then in the create shortcut
configuration in the icon file box type in C:\windows\customicons\customicon.ico
This is less than ideal, ideally the shortcut configuration should
allow you to upload a custom icon file from the computer you are
currently using and then the configuration should place it somewhere
on the targets computer and link it to the created shortcut. I
don't want the icon to depend on a network connection, the icon
file should be placed on the target locally.