Launch Powershell script from ARS Web Interface

Apologies for late reply guys and not being specific enough, I'll try to do that now.
JohnnyQuest was guessing quite good already.

I managed to suit my needs now, even if I had to "sell" another extension attribute for this but it's working fine.

I created a menu entry which updates the extension attribute which I "monitor" by way of the workflow which then executes the script, reading neccessary user information, generating the PIN and sending the welcome message.
Everything's working fine as expected.
Link is only been displayed if the user is EnterpriseVoice enabled on SkypeForBusiness
(msRTCSIP-OptionFlags being 385).

For the records, the script:

function LyncSendWelcomeMail ($Request)
{

# check if object is a user
if ($Request.Class -ne "user") {
return
}

# check if user is lync-enabled
$usertosend=(Get-QADUser $Request.DN -IncludedProperties msRTCSIP-UserEnabled -DontUseDefaultIncludedProperties)."msRTCSIP-UserEnabled"


if ($usertosend -ne $true) {
return
}

# open remote PowerShell session to SfB Server
$username = <username>
$pwdTxt = <not needed to mention>
$securePwd = $pwdTxt | ConvertTo-SecureString
$credobject = New-Object System.Management.Automation.PSCredential -ArgumentList $username, $securePwd
$lync_session = New-PSSession -ConnectionUri "https://<servername>/OcsPowershell" -Credential $credobject
Import-PSSession $lync_session

# get user mail address
$usermail = (Get-QADUser $Request.GUID -IncludedProperties PrimarySMTPAddress -DontUseDefaultIncludedProperties).PrimarySMTPAddress

# get user URI
$UserURI = (Get-QADUser $Request.GUID -IncludedProperties "msRTCSIP-PrimaryUserAddress" -DontUseDefaultIncludedProperties)."msRTCSIP-PrimaryUserAddress"

#define E-Mail from
$from = "<from_address>"

#define relay server
$smtpserver="<relayhost>"


# load function to send WelcomeMail
. C:\scripts\ps\SfB_WelcomeMail\sfb_welcome_mail.ps1

#send Welcome-Email
Set-CsPinSendCAWelcomeMail -UserEmailAddress $usermail -UserURI $UserURI -From $from -smtpserver $smtpserver -force

#close remote PowerShell Session
Remove-PSSession $lync_session

}

Apologies for late reply guys and not being specific enough, I'll try to do that now.
JohnnyQuest was guessing quite good already.

I managed to suit my needs now, even if I had to "sell" another extension attribute for this but it's working fine.

I created a menu entry which updates the extension attribute which I "monitor" by way of the workflow which then executes the script, reading neccessary user information, generating the PIN and sending the welcome message.
Everything's working fine as expected.
Link is only been displayed if the user is EnterpriseVoice enabled on SkypeForBusiness
(msRTCSIP-OptionFlags being 385).

For the records, the script:

function LyncSendWelcomeMail ($Request)
{

# check if object is a user
if ($Request.Class -ne "user") {
return
}

# check if user is lync-enabled
$usertosend=(Get-QADUser $Request.DN -IncludedProperties msRTCSIP-UserEnabled -DontUseDefaultIncludedProperties)."msRTCSIP-UserEnabled"


if ($usertosend -ne $true) {
return
}

# open remote PowerShell session to SfB Server
$username = <username>
$pwdTxt = <not needed to mention>
$securePwd = $pwdTxt | ConvertTo-SecureString
$credobject = New-Object System.Management.Automation.PSCredential -ArgumentList $username, $securePwd
$lync_session = New-PSSession -ConnectionUri "https://<servername>/OcsPowershell" -Credential $credobject
Import-PSSession $lync_session

# get user mail address
$usermail = (Get-QADUser $Request.GUID -IncludedProperties PrimarySMTPAddress -DontUseDefaultIncludedProperties).PrimarySMTPAddress

# get user URI
$UserURI = (Get-QADUser $Request.GUID -IncludedProperties "msRTCSIP-PrimaryUserAddress" -DontUseDefaultIncludedProperties)."msRTCSIP-PrimaryUserAddress"

#define E-Mail from
$from = "<from_address>"

#define relay server
$smtpserver="<relayhost>"


# load function to send WelcomeMail
. C:\scripts\ps\SfB_WelcomeMail\sfb_welcome_mail.ps1

#send Welcome-Email
Set-CsPinSendCAWelcomeMail -UserEmailAddress $usermail -UserURI $UserURI -From $from -smtpserver $smtpserver -force

#close remote PowerShell Session
Remove-PSSession $lync_session

}