Resupply/Milch Cows

[Rwearjr]

Hi All,
Please forgive if this question has already been answered, I have made several forum searches and have not been able to locate this topic.
I am currently in March of 1940 TWoS. I have tried on this patrol, (and on my previous) to either use the radio resupply or locate milch cows. Does anyone know if/ when these features enter into the game? After searching the web I was unable to locate any specific time period when the Germans began using Milch Cows.
Secondly, May I pull into any friendly port and resupply torps and fuel?

Last but not least, I have seen and read several times about using caution when applying promotions to the torpedo officer. Is this true for TWoS? If so, is it ok to apply promotion points to the "Torpedo Maintenance" and "Reload time" skills? As I have already done this (before reading I shouldn't.)

I have about 20 other questions, but always seem to forget them when I get around to posting. Special thanks to all the active posters here, and Extreme shout out to Vecko, and all the awesome mod community for turning the SH5 lemon into lemonade. I find something new on every patrol, and am impressed especially with the amount of work put into the AI. My example:

U-51 sunk a Cimmaron class tanker last night in the western approaches. There was a Tommy destroyer about 15Km to my 90* 180* true. The medium merchant trailing the tanker must have radioed the Royal Navy, or the destroyer heard the explosions because within about 2 minutes he was at flank bell headed straight for me. I attempted to surface and move out of the area at my own flank bell, but he was doing around 30+ knots. He closed the gap in no time, and forced me under by shelling me. I took some minor damage and flooding, and was bloody fortunate to have most of it under control before he was on top of our last visual location. I dived to 120 meters, and deployed a decoy as soon as I got under at around 20 meters. He spent about ten minutes depth charging my last known location, giving me precious time to creep further away and continue repairs. The entire scenario lasted about 3 hours with him passing directly over top of me 3 times and dropping depth charges all around us. To a great sigh of relief he gave up and went back to his former location. I then made mistake 2 by surfacing. I don't think he actually spotted me because he was 11+Km away when I surfaced, he just turned around and came back to see if I was there. He fired on me again. I quickly dove and repeated the decoy trick again once he was around 5000 meters away. Almost same scenario again, except we were under about 4 hours this time. He finally gave up at nightfall, and I crept away at PD until he disappeared from my hydro/ visual, and it was dark.
As we were leaving the area (again at flank bell) a second destroyer which I can only assume came from afar due to the previous radio call arrived on the scene and poked around for about 30 minutes (maybe more but I lost visual on him) Luckily we were long gone from the area by then. We later tracked down , and sunk the medium steam merchant as payback! Thank you TWoS and mod community again for an awesome experience.
Whew! Great stuff.
Rolf Weare U-51, (Ex U-37)