Using expression in Azure key vault task?

Hello,

This is giving invalid key vault name. Does Azure key vault task accepts expression. If not then how to pass the value to azure key vault in such scenario

variables:
- group: env_map
- name: qaNamespace
  value: $[coalesce(variables[variables['Build.SourceBranch']], '')]
 


- task: AzureKeyVault@2
displayName: Download Secrets from Key Vault
inputs:
azureSubscription: ${{parameters.azureSubscription}}
KeyVaultName: replace(replace(replace(variables['qaNamespace'], 'a', 'vault1'), 'b', 'vault2'), 'c', 'vault3')
SecretsFilter: 'PASSWORD,UserID'
RunAsPreJob: false