authentication - Authenticate Powershell script on SharePoint site using Claims -

i have following problem:

my team uses sharepoint team site, delivering our work among other things. sharepoint developers , write lot of powershell, far site concerned, mere users, not admins. wrote scripts upload , download documents , site. here's simple example of did:

$credentials =  get-credential  ​....  download-file -url $fileurl -destination $destination -credentials $credentials 

the get-credential function causes username/password dialog pop up. worked until provider of site change method of authentication claims. 403:

"the remote server returned error: (403) forbidden."

i've been googling time, got lot of articles on how set claims authentication on sharepoint web application. admin stuff, of no use me, don't have necessary permissions on site. need example of how use it. how authenticate using claims powershell. because providing credentials gained via get-credential no longer enough.

additional info: i'm using correct credentials, work when try log on site manually via browser. have full rights file i'm trying access. we're using powershell version 2, developing sharepoint 2010. site i'm trying authenticate (most likely) sharepoint 2010 too. thank in advance.