I am afraid that currently you will only be able to see preferred stocks in synced brokerage accounts.
We list tickers and prices of the preferred stocks you own on all synced brokerage accounts. However, you won't see gains, losses or price changes for your preferred stocks due to a lack of intra-day pricing data. All data will appear only when it is pulled from the brokerage nightly.
We currently don't offer the functionality of tracking preferred stocks in portfolios you created manually.