@IGX, for peso denominated preferred shares, I believe you can use any of the PSE brokers. However, the Dollar denominated preferred shares (ex. Del Monte), there are a few accredited brokers. Buy and Sell just like any other stocks.
For new preferred shares offering, you can inquire with your banks. Normal Underwriters, based on my experience, are BDO, China Bank, and RCB.
Peso denominated preferred shares dividends are taxed at 10% while no tax for Dollar denominated shares. Interest ranges from 5 - 8% on peso denominated. Dollar denominated shares like Del Monte is at 6.5%.
Bought a few dollars when it was doing around 45 - 50 Php and bought the Del Monte preferred shares from the bank. Dividend is paid semi annually. (For peso denominated, it is usually paid quarterly).
Cover na ung pang travel yearly courtesy of Del Monte
BTW for corporate bonds, two new ones coming AFAIK. SMC Global at around 6 -6.75% and Century Properties at 7 - 8%.