Partitioning on a MBR table disk fails (and destroys my data...)

Hello,

I had not been succesful in partitioning and MBR disk for FreeBSD.

I have only one free primary partition where I had installed NetBSD and OpenBSD alternatively since many years.  The free space on the disk is divided into three parts: one for NetBSD, one for OpenBSD and one left for FreeBSD. When I did change from one BSD to the other I edited the MBR (start sector, end sector and type a6/a9).

Before now installing FreeBSD for the first time (did use qemu in the past) I adjusted the sectorss to the FreeBSD range and changed to type a5, then erased the first sectors of that partition.

While NetBSD and OpenBSD autoselect their a9/a6 partitions, FreeBSD sees it's partition but doesn't allow to add BSD partitions for e.g. / or swap (no space left...). So I deleted the prepared partition and added a new one. The size the tool told me was too large (sum of free space on the disk) but after it was added a different size had been shown--that which I had reserved for FreeBSD (so there is a bug in the install tool). After installation I saw that it had overwritten the over BSDs data.

1) Why does FreeBSD not simply use the free partitoin that I had prepared for it? It had detected that it is erased, why just doesn't it allow to add / and swap?

2) Why doesn't FreeBSD doesn't show where (on which sector) it adds a new partition? This and the loss of my data is really disappointing.

At the moment installing FreeBSD is impossible at my disk while the over BSDs did work out of the box.

Carsten